After a tragic car accident where his girlfriend Ryôko Ooyama (Nami Tsukamoto) died, Hiroshi Takagi (Tadanobu Asano) suffers amnesia with his memories completely blanked. When he sees a book about dissection, he decides to join the medical school with the support of his parents. In the dissection class, his group participates of the autopsy of a young woman, and while cutting apart the tissue, he partially recalls his accident. Later, when he sees a tattoo in the arm of the corpse, he discloses that she was his girlfriend and becomes obsessed to go further in the examination of the body.

In Tokyo, the freelancer cameraman Takuyoshi Masuoka is obsessed investigating the fear sensation near death. When he shots with his camera a man stabbing himself in the eye in the access to the subway, he seeks what the suicidal might have seen to experiment the same sense of horror the man felt when he died. He finds a passage to the underground of Tokyo where he meets a mysterious naked woman that does not speak and he calls her F. He brings F to his place and he has difficulties to feed her, until he discovers that she drinks blood. Masuika becomes a serial killer draining the blood of his victims to nurse F.