Nogizaka Haruka no Himitsu

Nogizaka Haruka no Himitsu (乃木坂春香の秘密) is a Japanese light novel series by Yūsaku Igarashi, with illustrations by Shaa. The series originally started serialization in volume thirty of MediaWorks' now-defunct light novel magazine Dengeki hp on June 18, 2004. One more chapter was published until the first bound novel of the series was released, though more chapters were later serialized in the magazine. The first novel was released in October 2004, and as of July 2010, 12 volumes have been published by ASCII Media Works under their Dengeki Bunko imprint. A manga adaptation by Yasuhiro Miyama was serialized in ASCII Media Works' Dengeki Moeoh between the October 2006 and August 2010 issues. An anime adaptation produced by Studio Barcelona aired between July and September 2008; a second anime season aired between October and December 2009. A visual novel for the PlayStation 2 was released in Japan in September 2008 and a second game for the PlayStation Portable was released for digital download in February 2010.

Plot
Nogizaka Haruka no Himitsu is set at the private high school Hakujō Academy in Japan and centers around the male protagonist Yūto Ayase and his classmate Haruka Nogizaka. While Yūto is rather ordinary, Haruka is very attractive, intelligent, and rich. Due to this, she is the school's most unattainable girl and is so idolized that her classmates give her the French nicknames Nuit Étoile (The Night Star) and Lumière du Clavier (The Piano's Light). One day, Yūto's good friend Nobunaga Asakura asks him to return a book to the school library, and when he goes to return it, Yūto stumbles across Haruka and her darkest secret—she is a diehard fan of anime, manga, and the otaku culture. Yūto promises to keep her secret hidden and the two become close friends. Yūto does his best to help Haruka with her secret hobby while developing his relationship with her.

Main characters

 * Yūto Ayase (綾瀬 裕人)
 * Yūto is the main protagonist of the story. He is an ordinary student who attends the private high school Hakujō Academy and is in his second year of high school. One day, he stumbles across his classmate Haruka in the library and discovers her hidden secret—she is a major otaku and loves anime and manga. Following this revelation, Yūto starts to hang out with Haruka which brings up the envy and jealousy of many of his fellow classmates. Yūto lives with his parents and older sister Ruko, though his parents are always working and thus are generally absent from home. He behaves bluntly and generally likes to be left alone. He has an average determination to study for school. Even though he and Haruka are so close, he sometimes believes since he is not wealthy he cannot officially be her boyfriend.
 * Yūto is the main protagonist of the story. He is an ordinary student who attends the private high school Hakujō Academy and is in his second year of high school. One day, he stumbles across his classmate Haruka in the library and discovers her hidden secret—she is a major otaku and loves anime and manga. Following this revelation, Yūto starts to hang out with Haruka which brings up the envy and jealousy of many of his fellow classmates. Yūto lives with his parents and older sister Ruko, though his parents are always working and thus are generally absent from home. He behaves bluntly and generally likes to be left alone. He has an average determination to study for school. Even though he and Haruka are so close, he sometimes believes since he is not wealthy he cannot officially be her boyfriend.


 * Haruka Nogizaka (乃木坂 春香)
 * Haruka is the main female character of the story, and is Yūto's classmate. Due to her beauty and intelligence, She is idolized at school and regarded as the school's most unattainable girl, even known by the French nicknames Nuit Étoile (The Night Star) and Lumière du Clavier (The Piano's Light). She is very skilled at playing the piano and has taken overall victories in international contests. She also has a gentle personality, is a natural airhead, and is quite clumsy. Her deep hidden secret is that she is a major otaku and loves anime and manga. In middle school, her secret was exposed and she received a certain amount of prejudice towards it which caused her to keep it a secret once she entered high school. When Yūto finds out about it, Haruka is relieved that he does not tell anyone or harass her about it. She also comes from a rich family and privileged upbringing, so her interest in the otaku subculture is looked down upon due to her status in society, which is another reason why she keeps it a secret. Haruka once fled to a park after being scolded by her father, several years before. It was here that her anime obsession started when Yūto gave her the first issue of Innocent Smile. While being very talented, she cannot draw well, but does not realize it because she is too proud of it for anyone to tell her directly.
 * Haruka is the main female character of the story, and is Yūto's classmate. Due to her beauty and intelligence, She is idolized at school and regarded as the school's most unattainable girl, even known by the French nicknames Nuit Étoile (The Night Star) and Lumière du Clavier (The Piano's Light). She is very skilled at playing the piano and has taken overall victories in international contests. She also has a gentle personality, is a natural airhead, and is quite clumsy. Her deep hidden secret is that she is a major otaku and loves anime and manga. In middle school, her secret was exposed and she received a certain amount of prejudice towards it which caused her to keep it a secret once she entered high school. When Yūto finds out about it, Haruka is relieved that he does not tell anyone or harass her about it. She also comes from a rich family and privileged upbringing, so her interest in the otaku subculture is looked down upon due to her status in society, which is another reason why she keeps it a secret. Haruka once fled to a park after being scolded by her father, several years before. It was here that her anime obsession started when Yūto gave her the first issue of Innocent Smile. While being very talented, she cannot draw well, but does not realize it because she is too proud of it for anyone to tell her directly.

Classmates and teachers

 * Nobunaga Asakura (朝倉 信長)
 * Nobunaga is a childhood friend of Yūto who attends the same private high school, though is in the class next to his. He has a cheerful and openhearted personality, gets very good grades, and is considered a bishōnen by the female students. However, he is a hardcore otaku and is familiar with the layout of Akihabara. He is extremely famous in various places in Akihabara. Due to his enormous amount of purchases, he is known as "Kaiser" at the Animate store, and is one of three people who possesses the golden Animate card. At a maid café where Haruka once worked part time called "@Home ~Café", there is a picture of him shaking hands with the manager of the café, framed in gold with the caption "Welcome home, our greatest master" hung in the center of the café. Covertly, he knows what is going on between Yūto and Haruka.
 * Nobunaga is a childhood friend of Yūto who attends the same private high school, though is in the class next to his. He has a cheerful and openhearted personality, gets very good grades, and is considered a bishōnen by the female students. However, he is a hardcore otaku and is familiar with the layout of Akihabara. He is extremely famous in various places in Akihabara. Due to his enormous amount of purchases, he is known as "Kaiser" at the Animate store, and is one of three people who possesses the golden Animate card. At a maid café where Haruka once worked part time called "@Home ~Café", there is a picture of him shaking hands with the manager of the café, framed in gold with the caption "Welcome home, our greatest master" hung in the center of the café. Covertly, he knows what is going on between Yūto and Haruka.


 * Yukari Kamishiro (上代 由香里)
 * Yukari (light brown hair, braided) is the vice-homeroom teacher to Yūto's class and is an old friend of Ruko. She is referred in the story by Yūto as the "sexual harassment teacher". She is constantly smiling, though she enjoys teasing trouble makers. She likes spending a lot of time over at the Ayase house, and is unmarried though wants a boyfriend. At school, she is in charge of teaching music. She is twenty-three years old, though refers to herself as "eternally seventeen". There is a possibility that she is the rumored teacher that graduated from this same school and famous in the music world as the Performer of the Sunset.
 * Yukari (light brown hair, braided) is the vice-homeroom teacher to Yūto's class and is an old friend of Ruko. She is referred in the story by Yūto as the "sexual harassment teacher". She is constantly smiling, though she enjoys teasing trouble makers. She likes spending a lot of time over at the Ayase house, and is unmarried though wants a boyfriend. At school, she is in charge of teaching music. She is twenty-three years old, though refers to herself as "eternally seventeen". There is a possibility that she is the rumored teacher that graduated from this same school and famous in the music world as the Performer of the Sunset.


 * Shiina Amamiya (天宮 椎菜)
 * Shiina is a girl who participated in the London Piano Contest with Haruka; Shiina ranked second after Haruka who ranked first. She transfers into Yūto's class at school. Her hobbies include playing the piano and the martial art of naginatajutsu. She always has a positive, cheerful and sociable personality. This makes her transition as a transfer student very easy. She used to live in Otaru, Hokkaidō, Japan, though does not speak much of those days. She shows an interest for Yūto as she believes there might be a reason they constantly bump into each other. She said one of the reason she chose Yūto's school to transfer to is because of a famous teacher who graduated from the school and is known as the Performer of the Sunset is teaching at the school.
 * Shiina is a girl who participated in the London Piano Contest with Haruka; Shiina ranked second after Haruka who ranked first. She transfers into Yūto's class at school. Her hobbies include playing the piano and the martial art of naginatajutsu. She always has a positive, cheerful and sociable personality. This makes her transition as a transfer student very easy. She used to live in Otaru, Hokkaidō, Japan, though does not speak much of those days. She shows an interest for Yūto as she believes there might be a reason they constantly bump into each other. She said one of the reason she chose Yūto's school to transfer to is because of a famous teacher who graduated from the school and is known as the Performer of the Sunset is teaching at the school.


 * Tōka Tennōji (天王寺 冬華)
 * Tōka is a student at Yūto's school, though she is in her first year, class three. She is known by the nickname Princess Blizzard at school because of her domineering and arrogant personality. She comes from a family whose wealth could rival that of Haruka's family. Her family is known as "The East Nogizaka's House and the West Tenōji's house". Yūto worked as her personal butler for one week before Christmas to earn money for Haruka's Christmas present. After the head of the family died at age 147, she became the third in line to inherit the family fortune. Her ultimate goal is world conquest. She cameos in the first season of the anime adaptation, but is fully shown in Purezza.
 * Tōka is a student at Yūto's school, though she is in her first year, class three. She is known by the nickname Princess Blizzard at school because of her domineering and arrogant personality. She comes from a family whose wealth could rival that of Haruka's family. Her family is known as "The East Nogizaka's House and the West Tenōji's house". Yūto worked as her personal butler for one week before Christmas to earn money for Haruka's Christmas present. After the head of the family died at age 147, she became the third in line to inherit the family fortune. Her ultimate goal is world conquest. She cameos in the first season of the anime adaptation, but is fully shown in Purezza.


 * Mai Asahina (朝比奈 麻衣)
 * Mai is a girl in Yūto's class. She generally has a quiet personality, though is vice-president of the naginatajutsu club. She is close friends with Shiina and Ryōko. She cameos in the first season of the anime adaptation, but is fully shown in Purezza.
 * Mai is a girl in Yūto's class. She generally has a quiet personality, though is vice-president of the naginatajutsu club. She is close friends with Shiina and Ryōko. She cameos in the first season of the anime adaptation, but is fully shown in Purezza.


 * Ryōko Sawamura (澤村 良子)
 * Ryōko is a classmate and close friend of Shiina and Mai, and is often seen with them. As opposed to the quiet Mai, she is quite boisterous and hyperactive. She often refers to Shiina as "Shiina-cchi" and Yūto as "Ayase-cchi". She notices that Shiina feels something for Yūto, so she (and Mai) encourages her to go for him, perhaps oblivious to the fact that Yūto has Haruka. She is mostly active in Purezza.
 * Ryōko is a classmate and close friend of Shiina and Mai, and is often seen with them. As opposed to the quiet Mai, she is quite boisterous and hyperactive. She often refers to Shiina as "Shiina-cchi" and Yūto as "Ayase-cchi". She notices that Shiina feels something for Yūto, so she (and Mai) encourages her to go for him, perhaps oblivious to the fact that Yūto has Haruka. She is mostly active in Purezza.


 * Nagai, Takenami, & Ogawa (永井・竹浪・小川)
 * (Nagai), (Takenami),  (Ogawa)
 * Nagai, Takenami, and Ogawa are a group of male students in Yūto's class. Everyone refers to them as the "three idiots" because they always get into idiotic discussions. These three wish for the same wishes every New Year, and get the same fortune slips that indicate terrible luck.


 * Mahiro Asakura (朝倉 真尋)
 * Mahiro is Nobunaga's younger sister. She is referred by her brother as a hopeless person with a poor sense of direction. She views Nobunaga as an idiot older brother, though she does like Yūto. She dislikes her brother's otaku hobbies. She does not make an appearance in the anime.


 * Keiji Sendai (千代 啓二)
 * (visual novel)
 * Keiji is Yūto's classmate; he is known as "mad dog". He calls himself a "natural enemy of Akiba-kei," though Yūto has seen him in Akihabara and at Comiket. He originally comes from Shaa's other manga series Kyōhaku Dog's. He only cameos in the anime.


 * Setsuna Yatsusaki (八咲 せつな)
 * (visual novel)
 * Setsuna is a girl in Yūto's class; she is known as "faithful dog Hachikō". She is considerably clumsy. She has been seen by Yūto together with Keiji in Akihabara and at Comiket. Like Keiji, she originally comes from Kyōhaku Dog's. She only cameos in the anime.

Ayase family

 * Ruko Ayase (綾瀬 ルコ)
 * Ruko (black hair, ponytail) is Yūto's older sister. She works as a private secretary to a company president. She is skilled in karate and is a 2-dan. She is a hard worker, though she drinks a lot at home and is unable to do any housework which makes Yūto in charge of all the chores. She generally has a rough attitude and will often speak in a brutish manner. Since her parents are absent so often, Ruko takes up the position as the highest person in the house with her brother. When first meeting Haruka, Ruko was very pleased with her, though Yūto regarded this as unusual. She is a weapon fanatic, which is proven by the fact that she owns many magazines about weapons. She also has her personal favorite Japanese blade called Ruri Dokuro, which means lapis lazuli skull. Her battle skills are considered at the professional fighter level. This is demonstrated when she completely broke the Tennōji's household security with Yukari looking for Yūto when he had to stay one week for his butler part time job and forgot to make food for them.
 * Ruko (black hair, ponytail) is Yūto's older sister. She works as a private secretary to a company president. She is skilled in karate and is a 2-dan. She is a hard worker, though she drinks a lot at home and is unable to do any housework which makes Yūto in charge of all the chores. She generally has a rough attitude and will often speak in a brutish manner. Since her parents are absent so often, Ruko takes up the position as the highest person in the house with her brother. When first meeting Haruka, Ruko was very pleased with her, though Yūto regarded this as unusual. She is a weapon fanatic, which is proven by the fact that she owns many magazines about weapons. She also has her personal favorite Japanese blade called Ruri Dokuro, which means lapis lazuli skull. Her battle skills are considered at the professional fighter level. This is demonstrated when she completely broke the Tennōji's household security with Yukari looking for Yūto when he had to stay one week for his butler part time job and forgot to make food for them.

Nogizaka family

 * Mika Nogizaka (乃木坂 美夏)
 * Mika is Haruka's younger sister in her second year of junior high school. Her hobbies include playing the violin, playing squash, caring for wild pigs, and spying on her sister and Yūto. She has a personality that is the exact opposite of her sister's, who is naïve. She enjoys Yūto's company and she often calls him "Onii-san" (an affectionate word meaning brother, brother-in-law, or a brother-like male figure). When Haruka is with Yūto, however, Mika likes to tease them. In contrast to her airhead older sister, Mika is very stable. Even at her young age, she is more knowledgeable about sex than Haruka, although she will get shocked or stunned mentally if exposed to H-rated material just like her sister. She shows some interest in Yūto after their date. She is deathly afraid of ghosts. She has been running for the student council president of her all girl school for two consecutive years. She is just as much as an idol as her sister at school and is known by the name Moonlight Strawberry.
 * Mika is Haruka's younger sister in her second year of junior high school. Her hobbies include playing the violin, playing squash, caring for wild pigs, and spying on her sister and Yūto. She has a personality that is the exact opposite of her sister's, who is naïve. She enjoys Yūto's company and she often calls him "Onii-san" (an affectionate word meaning brother, brother-in-law, or a brother-like male figure). When Haruka is with Yūto, however, Mika likes to tease them. In contrast to her airhead older sister, Mika is very stable. Even at her young age, she is more knowledgeable about sex than Haruka, although she will get shocked or stunned mentally if exposed to H-rated material just like her sister. She shows some interest in Yūto after their date. She is deathly afraid of ghosts. She has been running for the student council president of her all girl school for two consecutive years. She is just as much as an idol as her sister at school and is known by the name Moonlight Strawberry.


 * Gentō Nogizaka (乃木坂 玄冬)
 * Gentō is Haruka's and Mika's father. His last name is adopted from his wife's family. His speech and conduct makes him seem like a member of the yakuza, though he is a loving parent who dotes on his daughters. He even bought an entire island for Haruka's birthday. He is against Haruka hanging around Yūto so much (and he often draws his sword when he suspects Yūto is "doing something hanky-panky" with Haruka), though he does not mind having Yūto around when he is alone. He heads the family's private paramilitary strike force unit known as The Hell Hounds.
 * Gentō is Haruka's and Mika's father. His last name is adopted from his wife's family. His speech and conduct makes him seem like a member of the yakuza, though he is a loving parent who dotes on his daughters. He even bought an entire island for Haruka's birthday. He is against Haruka hanging around Yūto so much (and he often draws his sword when he suspects Yūto is "doing something hanky-panky" with Haruka), though he does not mind having Yūto around when he is alone. He heads the family's private paramilitary strike force unit known as The Hell Hounds.


 * Akiho Nogizaka (乃木坂 秋穂)
 * Akiho is Haruka's and Mika's mother. Despite having given birth twice, she appears youthful and beautiful, so young-looking and beautiful that Yūto originally thought she was Haruka's older sister or cousin when he first met her. She is a principal of a cooking school. She has a quiet and intellectual demeanor but has the strength to overcome her husband; in fact, she is referred to by Yūto and Haruka as "The Nogizaka house's ultimate weapon". In contrast to her husband, she thinks it is good that Haruka and Yūto spend time together, and she likes to watch the development of their relationship by joining in on spying on them. However, she is very strict that Haruka keeps up on her studies.
 * Akiho is Haruka's and Mika's mother. Despite having given birth twice, she appears youthful and beautiful, so young-looking and beautiful that Yūto originally thought she was Haruka's older sister or cousin when he first met her. She is a principal of a cooking school. She has a quiet and intellectual demeanor but has the strength to overcome her husband; in fact, she is referred to by Yūto and Haruka as "The Nogizaka house's ultimate weapon". In contrast to her husband, she thinks it is good that Haruka and Yūto spend time together, and she likes to watch the development of their relationship by joining in on spying on them. However, she is very strict that Haruka keeps up on her studies.


 * Ōki Nogizaka (乃木坂 王季)
 * Ōki is Haruka's and Mika's grandfather on their mother's side. He has a sociable personality and is a goodhearted old man. Although he is retired from his original position as the president of the Nogizaka's organization and became the consultant, he is still a very powerful man in the economic and political world. If he wants, all great leaders in the world will gather at one place for a high level conference within three hours. He has a shadow warrior named Heizō Sebastian Sakurazaka—Hazuki's grandfather.
 * Ōki is Haruka's and Mika's grandfather on their mother's side. He has a sociable personality and is a goodhearted old man. Although he is retired from his original position as the president of the Nogizaka's organization and became the consultant, he is still a very powerful man in the economic and political world. If he wants, all great leaders in the world will gather at one place for a high level conference within three hours. He has a shadow warrior named Heizō Sebastian Sakurazaka—Hazuki's grandfather.

Nogizaka family maids
The Nogizaka family maid team follows a ranking system. For some unspecified reason (and it seems that the Team are too scared to discuss the topic with Yūto), the second highest ranking maid is missing.


 * Hazuki Sakurazaka (桜坂 葉月)
 * Hazuki is the head maid of the Nogizaka family. She is mainly in charge of looking after Haruka and Mika, particularly Haruka; Hazuki acts in the way of an older sister towards her. She is generally very reserved and expressionless, but sometimes speaks of bombshell announcements. Hazuki adores cute things and even has a collection of stuffed animals. She often appears out of nowhere holding a chainsaw, her preferred defensive weapon.
 * Hazuki is the head maid of the Nogizaka family. She is mainly in charge of looking after Haruka and Mika, particularly Haruka; Hazuki acts in the way of an older sister towards her. She is generally very reserved and expressionless, but sometimes speaks of bombshell announcements. Hazuki adores cute things and even has a collection of stuffed animals. She often appears out of nowhere holding a chainsaw, her preferred defensive weapon.


 * Nanami Nanashiro (七城 那波)
 * Nanami is the third-highest ranking maid of the Nogizaka family, and she usually helps Hazuki with her work, but is more commonly found alongside Mika helping and joining in on her spying missions. She has a friendly personality and smiles a lot, though also has a wicked tongue. She is seen wearing sunglasses often. Like Hazuki, she also often appears out of nowhere, though holding a large hammer that looks like a meat tenderizer for a defensive weapon. She has a habit of driving extremely fast (she drives the family Rolls-Royce Phantom like a WRC driver, though she sometimes drives the other Nogizaka limousine), but Haruka just states she is a great driver when one is in a hurry.
 * Nanami is the third-highest ranking maid of the Nogizaka family, and she usually helps Hazuki with her work, but is more commonly found alongside Mika helping and joining in on her spying missions. She has a friendly personality and smiles a lot, though also has a wicked tongue. She is seen wearing sunglasses often. Like Hazuki, she also often appears out of nowhere, though holding a large hammer that looks like a meat tenderizer for a defensive weapon. She has a habit of driving extremely fast (she drives the family Rolls-Royce Phantom like a WRC driver, though she sometimes drives the other Nogizaka limousine), but Haruka just states she is a great driver when one is in a hurry.


 * Minamo Kusumoto (楠本 水面)
 * Minamo is the fourth-highest ranking maid of the Nogizaka family and in charge of finances, law, and public relations. She is very calm and refined in demeanor, and she easily commands attention and respect. She is practically second in command and becomes the head maid in case something happens to Hazuki.
 * Minamo is the fourth-highest ranking maid of the Nogizaka family and in charge of finances, law, and public relations. She is very calm and refined in demeanor, and she easily commands attention and respect. She is practically second in command and becomes the head maid in case something happens to Hazuki.


 * Maria Yukinohara (雪野原 鞠愛)
 * Maria is the fifth-highest ranking maid of the Nogizaka family. She does general work around the house, though she is mostly on the family medical treatment group.
 * Maria is the fifth-highest ranking maid of the Nogizaka family. She does general work around the house, though she is mostly on the family medical treatment group.


 * Koayu Nagikawa (凪川 小鮎)
 * Koayu is the sixth-highest ranking maid of the Nogizaka family, and is the head chef. She is extremely shy, and does not appear often.
 * Koayu is the sixth-highest ranking maid of the Nogizaka family, and is the head chef. She is extremely shy, and does not appear often.


 * Ayame Rokujō (六条 菖蒲), Sara Rokujō (六条 沙羅), Juri Rokujō (六条 樹里)
 * (Ayame), Momoko Ishikawa (Sara), Sayuri Yahagi (Juri)
 * Ayame, Sara, and Juri are three sisters who are all equally ranked the seventh-highest maids of the Nogizaka family. They are in charge of being chauffeurs to the family. The eldest sister Ayame flies an eight-passenger airplane (the Nogizaka business jet, the Winter Shogun), which is comfortable to ride. Sara, the middle sister, is very speedy when flying her plane, or driving her limousine, or her Harrier jump jet. Juri, the youngest sister, also flying a plane.


 * Alistia Rein (アリスティア＝レイン)
 * Alister, otherwise known as Alice, is the eight-highest ranking maid of the Nogizaka family, and is in charge of VIP security and sabotage. She looks like a grade school student, and is a blond Caucasian (most likely German, since she once utters "Bruder", which conveys the same meaning as Mika's "Onii-san", when addressing Yūto). She rarely speaks in the novel (being not yet skilled in Japanese), and normally converses with others via an array of nods and head-shakes to express her meanings (while uttering "koku"). However, in the second series, she is revealed to have superb fighting skills with the attitude of a programmed hell-bent killer, as she was revealed by Hazuki to be the one in charge of VIP security and sabotage.  She has a baseball bat studded with spikes, as well as spiked knuckles, as weapons.
 * Alister, otherwise known as Alice, is the eight-highest ranking maid of the Nogizaka family, and is in charge of VIP security and sabotage. She looks like a grade school student, and is a blond Caucasian (most likely German, since she once utters "Bruder", which conveys the same meaning as Mika's "Onii-san", when addressing Yūto). She rarely speaks in the novel (being not yet skilled in Japanese), and normally converses with others via an array of nods and head-shakes to express her meanings (while uttering "koku"). However, in the second series, she is revealed to have superb fighting skills with the attitude of a programmed hell-bent killer, as she was revealed by Hazuki to be the one in charge of VIP security and sabotage.  She has a baseball bat studded with spikes, as well as spiked knuckles, as weapons.


 * Rio Munakata (宗像 理緒)
 * Rio is the ninth-highest ranking maid of the Nogizaka family and in charge of the chemistry department.
 * Rio is the ninth-highest ranking maid of the Nogizaka family and in charge of the chemistry department.


 * Iwai Hinasaki (雛咲 祝)
 * Iwai is the tenth-highest ranking maid of the Nogizaka family and in charge of festivities. She also works as a real miko.
 * Iwai is the tenth-highest ranking maid of the Nogizaka family and in charge of festivities. She also works as a real miko.

Other characters

 * Milan Himemiya (姫宮 みらん)
 * Milan is a popular idol. Her posters and promotions for her song (which is the first anime adaptation's opening theme) are seen in the Comiket and in places around Akihabara. She is also working on the anime Nocturne Girls' School Lacrosse Club as a voice talent.  She turned Yūto into her manager upon knowing her real manager is on the other end of Japan, and later tipped Yūto of Yayoi's true plans for Haruka.
 * Milan is a popular idol. Her posters and promotions for her song (which is the first anime adaptation's opening theme) are seen in the Comiket and in places around Akihabara. She is also working on the anime Nocturne Girls' School Lacrosse Club as a voice talent.  She turned Yūto into her manager upon knowing her real manager is on the other end of Japan, and later tipped Yūto of Yayoi's true plans for Haruka.


 * Yayoi Kayahara (茅原 弥生)
 * Yayoi is a talent agent who is Milan's manager and the organizer of an idol audition that Haruka was asked to participate in. The truth is, they really wanted Haruka to be an idol, by all means necessary (that "idol audition" and the related processes are a fake, a ploy to draw in Haruka).  Haruka is absolutely unaware of what Yayoi is planning.
 * Yayoi is a talent agent who is Milan's manager and the organizer of an idol audition that Haruka was asked to participate in. The truth is, they really wanted Haruka to be an idol, by all means necessary (that "idol audition" and the related processes are a fake, a ploy to draw in Haruka).  Haruka is absolutely unaware of what Yayoi is planning.


 * Nozomi Kobayakawa (小早川 のぞみ)
 * Nozomi is Yayoi's partner as a talent agent. She usually fetches Haruka from school to the "lesson".
 * Nozomi is Yayoi's partner as a talent agent. She usually fetches Haruka from school to the "lesson".


 * Shute Sutherland (シュート・サザーランド)
 * Shute is the son of a wealthy family who is doing business with the Nogizaka family. He is an arrogant young man who looks down at common people—unlike his father. Oftentimes his arrogance leads him to trouble that ends up humiliating him. During Haruka's birthday, he bullies and tries to discourage Yūto from giving his gift to Haruka and brags about his multimillion-dollar gifts while belittling Yūto's, but ends up humiliated when he handles Ōki Nogizaka by the collar of his shirt, and his father demands that he apologize in front of him and Yūto, in front of a distinguished crowd (Haruka ignored him, anyway—she just greeted him out of courtesy). He is later demoted by his father to work as a butler "to teach him the value of humility," but to no avail, and earned trouble for himself at the Year-End Maid and Butler Convention.
 * Shute is the son of a wealthy family who is doing business with the Nogizaka family. He is an arrogant young man who looks down at common people—unlike his father. Oftentimes his arrogance leads him to trouble that ends up humiliating him. During Haruka's birthday, he bullies and tries to discourage Yūto from giving his gift to Haruka and brags about his multimillion-dollar gifts while belittling Yūto's, but ends up humiliated when he handles Ōki Nogizaka by the collar of his shirt, and his father demands that he apologize in front of him and Yūto, in front of a distinguished crowd (Haruka ignored him, anyway—she just greeted him out of courtesy). He is later demoted by his father to work as a butler "to teach him the value of humility," but to no avail, and earned trouble for himself at the Year-End Maid and Butler Convention.

Light novels
Nogizaka Haruka no Himitsu began as a series of light novels written by Yūsaku Igarashi, and drawn by Shaa. The series originally started serialization in MediaWorks' now-defunct light novel magazine Dengeki hp with the release of volume 30 on June 18, 2004. A second chapter was published in volume 31 of the same magazine on August 21, 2004. Less than two months later on October 10, 2004, the first bound volume of the series was published by ASCII Media Works under their Dengeki Bunko publishing imprint, and as of July 10, 2010, 12 volumes have been published. Additional chapters have also been published in Dengeki hp volumes: 34, 35, 41, and 47. The Mainichi Shimbun reported that as of January 2008, over 700,000 copies of the first seven volumes have been sold.

Manga
A manga adaptation was serialized in ASCII Media Works' seinen manga magazine Dengeki Moeoh between the October 2006 and August 2010 issues. The manga takes its story from the light novels that preceded it, and is illustrated by Yasuhiro Miyama. Four ''tankōbon volumes were sold under ASCII Media Works' Dengeki Comics imprint from November 15, 2007 to November 27, 2010.

Audio dramas
A four-episode radio drama, which first aired on October 27, 2007 aired on ASCII Media Works' radio program Dengeki Taishō. An hour long drama CD which adds to the story from the second episode of the radio broadcast was released on January 10, 2008. The voices provided for both dramas were the same, and the same cast was used for the anime adaptation.

Anime
Nogizaka Haruka no Himitsu was adapted into a 12-episode anime adaptation, and was broadcast in Japan between July 3 and September 25, 2008 on the Chiba TV broadcasting network. The anime is produced by Studio Barcelona and directed by Munenori Nawa. Six DVD compilation volumes were released by Geneon Entertainment between September 26, 2008 and February 27, 2009. A Blu-ray disc box set of the series will be released in Japan on September 26, 2009. The opening theme, "Tomadoi Bitter Tune" (とまどいビターチューン), is performed by Miran Himemiya and Chocolate Rockers. The ending theme, "Hitosashiyubi Quiet!" (ひとさしゆびクワイエット!), is performed by Kana Ueda, Mai Goto, Rina Satō, Kaori Shimizu and Mamiko Noto, the various voice actresses for the main characters of the anime collectively known as The N's.

A second anime series entitled Nogizaka Haruka no Himitsu: Purezza (乃木坂春香の秘密 ぴゅあれっつぁ♪) was announced for production in a pamphlet included with the tenth Spice and Wolf light novel volume. This series is again directed by Munenori Nawa and produced by Studio Barcelona under the name Diomedea. The second season aired 12 episodes between October 6 and December 22, 2009 in Japan. The opening theme is "Chōhatsu Cherry Heart" (挑発 Cherry Heart) by Milan Himemiya and Chocolate Rockers. The ending theme is "Himitsu Suishō! Uru to Love" (秘密推奨！うるとLOVE) by The N's (Kana Ueda, Mai Goto, Rina Satō, Kaori Shimizu and Mamiko Noto).

Visual novels
A visual novel based on the series for the PlayStation 2 developed by Vridge is published by ASCII Media Works and was released on September 25, 2008 in Japan entitled Nogizaka Haruka no Himitsu: Cosplay Hajimemashita (乃木坂春香の秘密 こすぷれ、はじめました♥). A second video novel, also developed by Vridge and published by ASCII Media Works, is titled Nogizaka Haruka no Himitsu: Dōjinshi Hajimemashita (乃木坂春香の秘密 同人誌はじめました♥) and was originally released as a five-part digital download online playable on the PlayStation Portable. A Universal Media Disc version of the game will be sold on October 28, 2010.