Ryuichi Fuyumi, a 16-year-old high school student, finds himself thrust into an extraordinary situation when he travels 30 days before the apocalypse started, just before a catastrophic zombie apocalypse erupts. A shy but perceptive individual, Ryuichi was an ordinary teenager with a keen interest in technology and survival tactics, hobbies that now prove crucial in his altered reality. Before the apocalypse, Ryuichi was known for his reserved nature and academic focus, often losing himself in books and digital games. However, his unexpected journey back in time has awakened a determined and resourceful side of him. Armed with knowledge of the impending disaster and the skills he's developed through his research and hobbies, Ryuichi is uniquely positioned to prepare for the crisis. Ryuichi is characterized by his calm demeanor and strategic thinking. His deep understanding of technology helps him create makeshift gadgets and defenses, while his survival skills, honed through extensive reading and practice, make him a valuable asset to any group of survivors. Despite his initial hesitations, Ryuichi evolves into a natural leader, driven by a blend of responsibility and the desire to protect those he cares about. As he navigates the tense days leading up to the apocalypse, Ryuichi faces the challenge of using his knowledge to avert or mitigate the disaster, all while grappling with the isolation and uncertainty of his situation. His journey is one of growth and resilience, marked by his efforts to balance the weight of knowing the future with the urgency of surviving the present.