Mutsumi Narita is a student whose voyeuristic habits draw frequent clashes with childhood acquaintance Megumi Iijima, though mutual concern lingers beneath their conflicts. Thrust into confronting replinoid monsters invading his school, the initially physically frail youth uncovers latent resilience and strategic ingenuity. His actions pivot around a romantic fixation on Saotome, whose abrupt disappearance propels him into investigating supernatural disturbances. Teaming with Iijima to track missing individuals, he emerges as an unlikely leader through sharp deduction and tenacity, eventually mastering advanced weaponry essential for battling replinoids—a shift from passive observer to determined protector. The story leaves emotional tensions unresolved, with Saotome’s fate remaining an open wound. His exchanges balance impulsive humor with sobering confrontations of mortality and loss among peers. The narrative confines itself to the OVA’s events, offering no further exploration of his past or future beyond the central crisis.