One day, Ayumi hears from her coworker Kotomi a rumor that a nurse at a nearby abandoned hospital wing is being used as a test subject for a new drug. That night, the two head to the derelict ward to uncover the truth, only to discover the hospital's dark secret. A female doctor named Kuromi has been kidnapping nurses and using them as experimental subjects in her research on human "regenerative cells." Soon, Ayumi and Kotomi are captured and subjected to the same fate—condemned to have the new drug applied directly into their rectums.