Kei Kurono es un estudiante egoísta y apático que se ve obligado a salvar a una persona de morir atropellada por un tren subterráneo debido a que, su compañero de la infancia Masaru Kato, lo llama para que le pueda ayudar, muriendo él y Kato en el intento. Enseguida aparecen en un apartamento aparentemente común con otras personas igual de desconcertadas que ellos. Allí, una misteriosa esfera negra les obliga a participar de un sádico juego y para ello les pone a su disposición todo un exótico arsenal futurista que deberán aprender a usar para combatir razas de aliens y otras amenazas que, para la gente común, pasan desapercibidas.
Los que llegan a la habitación no son vistos por los humanos mortales hasta que la esfera no los «suelta» después de cada misión. Una vez que cumplen una misión pueden llevarse el equipo que se les entrega - un arma, un traje especial... - a su casa o a dónde quiera que vayan.
Para cada misión se les da un tiempo limitado y cada vez que vuelven a la habitación, si es que sobreviven, se les otorgan unos puntos dependiendo de cómo actuaron al enfrentarse al objetivo. Esos puntos pueden, al acumularse 100, ser intercambiados por otra oportunidad entre los vivos.

Akira Inugami is a new exchange student at Hakutoku Middle School, but there is another side of him that is secret and hidden. He is a werewolf.
The story begins with the Homeroom teacher Akiko Aoshika walking home drunk, suddenly trips and is saved by Akira Inugami who then proceeds to walk away. Ms. Aoshika sees that he is a student and pursues him only to be jumped by Inugami's old school rivals. The gang attacks Inugami without mercy and seems beat him to death and yet he keeps getting back up. They then hit him with a car and he appears dead, they began to ruffle through his pockets. Ms. Aoshika faints soon after witnessing it and then Inugami takes his true form, the form of a Werewolf and destroys the gang. When Ms. Aoshika awakes, she finds the gang dead around her and is escorted to her school by the police only to find that Inugami is her new exchange student.

Fran is a girl created by Dr. Naomitsu Madaraki, the world's top biologist. Originally intended to be his assistant, she has overtaken his work and home while he is away. Her life is rather uneventful until various medical cases begin falling into her lap, ranging from resurrection to aesthetic surgery. There is a fair amount of black humor, nearly each story ending with Fran having created some sort of gruesome monstrosity or misfortune of and upon her patients, though seemingly content with the results.