One day in 1983, off-duty policeman Reiden picked up suspicious "father and daughter", Kei and Ai on his car. They are very close in age. Reiden is involved in fighting with them and the female fighter K2 who chased them. Kei who is drawn out his latent ability to the maximum by a Legendary "Trigger" Ai blows away K2. Then, the night sky split and strange space is showing from the slit. Their enemy is the secret society "Fraud" of para-psionics commanded by Kuu Ragua Lee. Kei, Ai and Reiden meet the assassinators whom "Fraud" sends out one after another.
- Ai is Headmeters who escaped from Fraud with Kei; (but she doesn’t have the operation yet). The original name is "I2". She is a clone of Kei’s lover Etsuko (= "I") killed by Fraud, and adores Kei as a father.
- Fraud suspects that she is legendary "Trigger" who draws out others' dormant faculty and amplifies it, and so pursues her.
- "2" of "I2" means "The second generation of the clone of Headmeters I". However, nobody of Headmeters knew who are "I" and "I2". And there is no information about the two persons also in the memory bank of Fraud's computer, and "Headmeters I" is a missing number. It is not clear why they recognized "I" and "I2", but the two people did not exist actually.
- K (Kei)
- Kei is Headmeters who escaped from Fraud to defend Ai. He was anesthetized suddenly and was made to undergo the operation for Headmeters on college days. And, he was given the code name "K". He was even proud of being Headmeters, but he became despondent because his lover Etsuko died from the same operation as him. Then, a girl appeared. She is just like Etsuko, but is ten years younger than Etsuko. She introduced herself as Ai-"I2"-. "I" was a code name of Etsuko. Kei decided to behave as her father.
- Kei has both ability of Headmeters and Tuned-man exceptionally, because Kuu Ragua Lee, the leader of Fraud, operated on Kei in person. However, he is a defect product as Headmeters, and he has only the faculty for incomplete mind reading. The number of his headmeter has risen only to level 5 by the shock of Etsuko's death, but the number rises to infinite (∞) when Ai draws out his latent abilities. His performance as Tuned-man is less than 1/10 of the output of Yi or Lyan, but Fraud performed the operation which is different from them on the body of Kei. Sensors which are embedded on the 108 vital points of his whole body control his muscles and internal organs, and brain, and he can always utilize his whole muscles 100% (people usually use them only about 20%).
- The stray cat which touched the topology wall, and lost the tail. Ai brings along the cat after she treated the injury.
- Reiden Yoshioka
- The obliging policeman involved in fighting of Kei and Ai vs. Fraud. 34 years old. He is automania, and his own car is Alpina based on BMW cars. He is in a dilemma between his wife Akemi and K2 currently charmed by him.
- K2 is Kei's feminized clone who was born by the chromosome manipulation. She is a high-ranking Headmeters of Fraud who is the same level as Mr. J in capability, and commanded the pursuit corps to Kei and Ai.
- She loves Kei by fervent narcissism and demands him to love her. Then, she wants to kill Ai who monopolizes his love. However, she lost memory and regressed to her infantile state of mind by touching the topology wall. And she took to Reiden who saved her. She recovers her memory later, but she does not change her mind
- Lee is an old security guard of a supermarket. He looks after Ai from Kei. He is a very kind old man, but is a mysterious man who is actually Headmeters of level 100.
Residents of floor 1983
- Akemi Yoshioka
- Akemi is a wife of Reiden, and she dominates him. She is possessed by Alloy and is made the puppet by it.
- One of hoodlum group of 3s. He is a little man with suspenders.
- Alloy possesses him and manipulates him any way it wants.
- They bear a grudge against that Reiden reported their injustice in the university entrance exam to the police, and they ambush him at his home and attack him. They had parents hush up the rape and the violence till then.
- One of hoodlum group of 3s. He is a big-boned man. He is pushed away on a road by Sugiura controlled by Alloy, and is run over by a car.
- One of hoodlum group of 3s. He is a foppish man who wears sunglasses, dyed hair brown and has a permanent. He shoots Reiden with a gun, but the bullet is teleported to the inside of his body, and he dies.
Residents of floor 2183
- Kuu Ragua Lee
- The leader of "Fraud" which is the highest consultative body of "Floor 2183", and also manages "Floor 1983". Supported by Headmeters with supernatural power, he is in opposition to the chief delegate Lai Lou Chin. He himself is Headmeters, and his level is 100.
- He is a skinhead and a brawny big man. He equips his head with the metal electronic device which covers his eyes, mouth, and his forehead.
- He believed that he was the governing classes who have managed the human beings of Floor 1983 who will live in 1983 fixed forever. But, he notices that he is also a captive managed by higher-ranking managers (inspectors) like them. Then, he decides to challenge them to fighting.
- J (Mr. J)
- Mr. J is a high-ranking Headmeters of Fraud and his level is 40. He is a sexless youth of long hair.
- He is Kuu Ragua Lee's page boy, and admires and loves him. He always fears that Kuu Ragua Lee loses the concern about him.
- He commands the operational unit which pursues Kei and Ai.
- A (Miss A)
- Miss A is a leader of Headmeters, is Kuu Ragua Lee’s right-hand woman, and is a daughter of the Coedes family.
- She is a muscular woman. There is her younger brother "B" in Headmeters.
- Yi is a secret agent of Fraud. He is a Tuned-man who was converted by Fraud with fighting power at the same level as a tank. He can shoot rays from his finger-tip.
- He is dressed in black from head to toe. He wears Mao suit, the glasses of a round frame and a black hat.
- He makes a combination with Lyan and chases Kei and others together.
- Lyan is a partner of Yi and is Tuned-man converted by Fraud as well as Yi. His clothes are full of black like Yi, too. He is killed by "Cat" which had power amplified by Ai.
- Talkative dolls
- "Talkative doll" is a general term for human robots (androids) which serve as an operator in Fraud headquarters. Their appearance resembles a naked middle-age man with a skinhead.
- Lai Lou Chin
- Lai Lou Chin is a chief delegate of "Floor 2183" and is the only person who opposes the leader of Fraud, Kuu Ragua Lee. He is a poor-looking old man of a bobbed hair style. He always soaks in a capsule filled with special solution in the nude. The capsule is set in the position ranging from the body to the head of the large-sized humanoid robot. Actually, the robot serves as a substitute for the body of Lai Lou Chin, and the capsule has the function to prevent "mind reading" of Headmeters. He is called "Enema head" by Miss A, because the form of the capsule resembles a disposable syringe.
Residents of the upper floor
- Alloy is in the floor upper than the floor where Ai and Kei are, and sent only speculation into lower floors from there.
- The identity of Alloy is a thing invented based on "Program alloy" which is against Ai and tries to incorporate the gene in itself when it finds the gene that the program does not have. Alloy was invented by incorporating the program in a monster cell discovered by chance. Alloy stores billions of human beings' gene in the cell.
- Since Alloy is an infinite form, it interferes in the world by getting into an organism and controlling the consciousness of that. However, the host of which Alloy influenced consciousness becomes very suggestible.
- Alloy possesses "Cat", a staff of Fraud, Sugiura, Yoshioka, Akemi, the artificial body of Lai Lou Chin in sequence, and handles their body.
- Alloy can draw out potential capacities of those whom Alloy touches and possessed like Ai.
Residents in A.D. 1983
- Lee Kuwabara
- Kuwabara is the head of Kasuga lab which existed in Shizuoka Izu in Japan once. He won fame as a professor of the bionics department of Los Angeles Institute of Technology. However, he was expelled from the bionics society, because he repeated medical experimentation on a living person to make a person with supernatural power artificially. When he was out of work, Sosuke Kasuga, his best friend and the head of Kasuga lab, gave him a job. Kuwabara assumed the head of the Kasuga lab after Sousuke's death, but Kuwabara betrayed Sosuke and his son after all, and returned to the society thanks to the program that they had studied.
- He is the original of Kuu Ragua Lee and old Lee. The two are his clone.
- Kasuga is the son of Sosuke Kasuga, the former head of Kasuga lab, and is the research worker.
- He lost his father and wife and daughter in a traffic accident at the same time in 1980.
- He completed "Program Ai" which Sosuke had studied.
- He is the original of Kei.
- "Floor" is a cylindrical world of a radius of 440km which extends concentrically with centering on "Fraud Building (=The Pillar of God)" as center point and is surrounded by topology walls.
- "Fraud" is para-psychicers' groups, they are considered to be a national prime consultative body in Floor 2183.
- Kuu Ragua Lee violated custom, and established headquarters inside of "The Pillar of God" where he calls "Fraud Building". He lives in there.
- "Headmeters" are members of Fraud using para-supernatural power.
- They analyze others' brain waves by many electronic devices buried in their body and read their minds (para-telepathy). And they control a magnetic field and float in the air and move an object (para-levitation and para-psychokinesis). And they predict what will happen in the near future at high hitting ratio by communicating with the city computer directly (para-precognition).
- When they show their ability, their forehead displays the number suitable for the degree.
- They occasionally equip the power supporter which is the heavy armaments for anti-Tuned-man warfare.
- Tuned-man (Cyborg)
- "Tuned-men" are combat cyborgs to whom the artificial muscle, the metal skeleton, etc. are transplanted, and they are equal to a tank in fighting power.
- It is especially easy to read their minds for Headmeters.
- "Diver" is a pet name of new and powerful mobile sky soldier or combat flying boat that Lai Lou Chin lent to Kuu Ragua Lee. Diver is a military escort for Kuu Ragua Lee to counter a new enemy, Alloy. Diver is a disk type and is propelled by a jet engine. Diver divides into 2 parts, and the upper part (Diver1) transforms into a combat humanoid robot. The lower part (Diver2) can be used as a flying boat as it is after separation.
it is sometime in the future and the anime starts off with Kei and Ai running for their lives. Ai is a girl who holds a terrible secret which could destroy the current world. The world is now populated by Headmeters, people who have psychic powers and their strength is shown on their forehead when they fight. However, Kei was an experimental subject and his strength never went above level 5 while other surpasses his ability effortlessly. In escaping, when in desperate moments, Kei could increase his ability to infinity when Ai is in trouble. And then the one who is after her have a deep secret, aided by a small dwarflike man living in a robotic suit. Eventually Ai is captured and Kei, a Sherlock Holmes detective and another Headmeter who was converted to the good side when Kei unleashed his horrible powers through Ai must go and rescue her. Together they must save Ai and the secret which she holds. What is the secret of Ai?? Who is she?
Ai Ai is a girl who holds a terrible secret which could destroy the current world.
Kei a human who is a test subject for the headmeters he escapes their grasp. Kei was an experimental subject and his strength never went above level 5 while other surpasses his ability effortlessly. In escaping, when in desperate moments, Kei could increase his ability to infinity when Ai is in trouble.
Reiden The private detective who helps Kei and Ai. He is a former police officer.
K2 Headmeters, she becomes an ally of Ai and Kei.
Kuu Ragua Lee Headmeters, he is a leader of Fraud.
Lai Lou Chin Old Headmeters with artificial body.
Alloy Gene polymer
Mr. J Headmeters
Headmeters Headmeters are people who are psychics and have supernatural strength this shows on their forehead when they fight.
Tuned-man Human beings converted for combat.