Sora, a man with no memory of his identity, is hospitalized at Cross Hospital after being found severely injured. The facility's director, Reika Rikage, offers him a large sum of money to serve as a test subject for a mysterious new medicine, assigning Nurse Yuu Yagami to oversee his care. As Sora navigates his new life, he develops a volatile and sexually charged relationship with Yuu, while the hospital's sinister motives begin to surface.