Sora is discovered critically injured before a hospital, suffering severe trauma from a rural village bicycle accident. Nurse Yu Yagami provides emergency care upon his rescue and hospitalization. Lacking relatives and perceived as physically resilient, he is transferred to a special ward by Hospital Director Reika Mikage. Director Mikage recruits him as a test subject for an experimental virility drug, citing his isolated status as practical for the study. Yu Yagami is assigned as his primary caregiver throughout the trial.

As an experiment incentive, Director Mikage grants him authority for intimate activities with Yu Yagami and other staff. This permission catalyzes increasingly erratic behavior, including aggressive advances toward multiple nurses. The experimental drug heightens impulsivity and sexual compulsions, driving him to pursue encounters across the hospital. During this period, he discovers confidential information documenting nurse Hiyori Kisaragi's compulsive sexual disorder. This discovery leads to his participation in Kisaragi's independent psychosexual experiments, further entangling him in the hospital's covert operations.

His relationship with Yu Yagami remains complex; she maintains professional concern for his well-being despite his actions, creating tension between her duty and his exploitation of the granted privileges. The drug's effects exacerbate his psychological instability, culminating in acts harming Yu and others. The experiment's unresolved conclusion leaves his ultimate fate ambiguous, with narrative threads hinting at potential consequences for his actions and the drug's long-term impact. His trajectory depicts a shift from vulnerable patient to active participant in the hospital's exploitative systems.