Todo is a rich businessman who is very demanding of his children. All three suffer from unexplained headaches that the doctor dismisses as migraines. After the family's eldest son commits suicide, Todo begins putting pressure on his second son Eiichi. His daughter Miho enforces the house rules, even going so far as to drag Eiichi home while he was visiting his friend Tsukasa. Tsukasa is shocked at the way Miho looks and behaves, since she never used to be like this. Eiichi argues with his father and is ordered to leave the house. He rebels by riding out onto the highway; where he lies down in the road and is hit by a car.
At Eiichi's funeral, his friends believe he committed suicide. Tsukasa reflects on how Eiichi used to get headaches and do reckless things that he later didn't remember. Also, Miho has no memory of going to Tsukasa's house or fighting with Eiichi. The Todo family also believe Eiichi's death was suicide. Todo says that his family has a long history of suicide and he thought he had broken the "curse" by working to become successful. He is angry that his sons would choose to die.
Miho is lonely without her brother, so Todo asks Tsukasa come to the amusement park with them. He takes a nap while the kids have fun. Miho gets another headache and soon starts to behave strangely, flirting with Tsukasa and almost jumping out of the Ferris wheel. She asks Tsukasa about the night Eiichi died and now seems to remember what happened. Her eyes glaze over and she takes on the strange look she had when she came to Tsukasa's house. She climbs onto the roof of a building and jumps off, but somehow doesn't seem to be hurt. When Tsukasa runs to get Todo, Todo's eyes have taken on the same glazed look.
As Miho grows up, she continues to have headaches and violent fits, referring to her "cursed bloodline." Mrs. Todo tells her she must learn to live with it or Todo will kill her. Todo warns Miho against dating boys, and is angry that he found a love letter to her from one of her classmates. The next day, she discovers that the boy is seriously injured after someone pushed him down the stairs. She realizes that she herself did it, and her headaches and strange behavior are caused by her father possessing her body. When his sons became too troublesome, he caused them to commit suicide; and now that his wife is expecting another baby, he wants to kill Miho.
Miho tries to tell Tsukasa what's happening to her, but collapses in pain. Todo takes over her body completely, throwing Tsukasa down the stairs like the other boy and warning him to stay away from Miho. Tsukasa arranges for Miho and her mother to stay with his aunt, but as they are leaving his house, Todo appears. He succeeds in possessing Miho but Tsukasa holds him off. Mrs. Todo says that she is leaving him, and finally she departs with Miho. Todo explains to Tsukasa that he always had to work hard and wasn't able to have any fun when he was young, so he learned to possess his children's bodies as a way of living through them. He didn't intend for it to go this far. Tsukasa offers the use of his body but Todo says it only works with his own children. He has realized he must let Miho go.
The following day, Todo goes to the amusement park and enjoys the rides by himself before jumping out of the Ferris wheel to his death as he tried to make Miho do.