Kajiki Hidemaru, Chu-san, and Yuki are patients at a psychiatric hospital in Komoro, Nagano Prefecture. Hidemaru killed his mother and daughter-in-law. Chu-san used to work as a salaryman, but he suffers from auditory hallucinations. Yuki is a high school student and she refuses to go to school. Due to that, she receives outpatient treatment. Patients at the psychiatric hospital try to live brightly, but things suddenly change. A murder takes place at the hospital. The murderer is Hidemaru.