Shugo (Kentaro Sakaguchi) is a doctor working the night shift in a nursing hospital. A man in a clown mask and a gun appears in the middle of the night. He brings Hitomi (Mei Nagano), a university student with a gunshot injury. The masked man takes the entire hospital hostage and the phone lines have been cut. Shugo and Hitomi try to escape the gunman while discovering deeper mysteries about the hospital, hidden rooms and conspiracies.