The film begins with a six-year-old girl being rushed into a hospital ER with an unusually distended stomach. Doctors begin to operate and find a disembodied head, Tomie's head, alive and growing inside the girl's belly. The head is placed in a tank of alkaline solution in the basement of the hospital for further observation. Soon after, all five of the hospital workers present during the operation mysteriously leave the hospital or disappear entirely, including hospital Director Morita.