Fuminori Sakisaka is a young medical student, whose life is changed when he gets in a traffic accident which kills his parents and leaves him heavily injured. Fuminori undergoes experimental brain surgery to save his life, but the surgery has an unintended side-effect - it creates a form of agnosia, causing his senses to become "warped". Everything he sees looks as if they were made out of flesh and human organs, people resemble monsters of rotten flesh in appearance and voice, and food that normally appeals to him tastes disgusting.
As he contemplates suicide in the hospital, Fuminori meets a beautiful, human looking girl among the flesh-covered walls. She introduces herself as Saya, and is apparently looking for her father. Fuminori does not want to be separated from Saya, and asks her to live with him. She agrees.