Ryo Tanaka, a struggling college student, works tirelessly at multiple part-time jobs to make ends meet. In a bid to earn some extra cash, he volunteers for a paid drug research study, unaware that it will alter the course of his life forever.

The experiment takes a disastrous turn, leaving Ryo bedridden with a high fever for several days. But when he finally awakens, he finds himself in a world plunged into chaos. A deadly virus has ravaged the city, turning its inhabitants into ravenous, flesh-eating zombies. Streets once bustling with life now lay desolate, the remnants of civilization crumbling under the weight of the apocalypse.