A plague sweeps the globe in 2030, transforming infected humans into grotesque creatures called Gibias. The virus mutates differently depending on age, gender, and race, creating an unpredictable parade of horrors across a devastated landscape. Japan becomes a warzone of monsters and desperation. Then two warriors materialize from centuries past: a samurai and a ninja ripped from the Edo period into this nightmare future. They're joined by a determined doctor racing to develop a cure before humanity vanishes entirely. Together, this unlikely trio moves through the wasteland, fighting off waves of Gibias while dodging roving gangs of survivors turned predatory by hunger and chaos. What emerges is survival horror with a samurai edge. The period-displaced warriors bring sword skills to a gunless apocalypse, but old weapons mean nothing against a shapeshifting biological threat. Every journey segment pits them against both monsters and human cruelty, forcing constant choices between mercy and self-preservation. The series balances visceral action with genuine dread, asking whether courage from a different era can matter when the world itself has become the enemy.