Hibiki Mamiya, a dedicated mechanic, plans to propose to his high school sweetheart, Kurumi Ogasawara, after years of romance. However, on the eve of his grand gesture, Hibiki becomes trapped in a highway tunnel following a mysterious and catastrophic cave-in. When he finally escapes days later, the vibrant world he once knew has vanished. Society has collapsed, and a terrifying zombie apocalypse, locally dubbed the "Golem" crisis, has overrun Japan. The streets are desolate, and flesh-eating monsters roam everywhere. Driven solely by his desperate love for Kurumi, Hibiki embarks on a perilous journey across the wasteland, determined to find her and fulfill his promise.Upon reaching Kurumi’s last known location, he discovers she has been evacuated, setting off a relentless quest of survival and heartbreak. Hibiki joins a ragtag group of desperate survivors taking refuge in various apocalyptic strongholds, including a shopping mall and heavily guarded quarantine zones. Along the way, alliances are forged, betrayals are uncovered, and human cruelty often proves more dangerous than the Golems themselves. Hibiki transforms from an ordinary, hopeful mechanic into a ruthless, hardened survivor, willing to do whatever it takes to protect those he cares about and secure a future.The narrative intensifies when Hibiki finally tracks Kurumi down, only to find she has been working as a
medical researcher under the
authoritarian control of the mysterious "Special Research Institute." Kurumi has changed, deeply burdened by scientific experiments and the desperate search for a vaccine. Tragically, she becomes infected with the Golem virus, sparking a devastating internal conflict for Hibiki, who must grapple with whether to end her suffering or find a cure.As the series progresses into later seasons, the scope expands into a brutal sci-fi survival thriller. Hibiki is thrust into dystopian island laboratories, political conspiracies orchestrated by a shadowy elite group known as "The One," and widespread human experimentation. He discovers the existence of a genetically superior human clone—his exact double—who complicates his relationship with Kurumi. Through escalating tragedies, the loss of close comrades, and overwhelming odds, Hibiki’s core motivation never wavers. He fights tirelessly against tyrannical regimes, rogue military factions, and hordes of the undead, all in a desperate battle to reclaim his humanity and salvage a future for the woman he loves, proving that devotion can endure even as the world literally ends around them.