面对庞大的魔神大军，为了回避全灭危机，勒库对伙伴们说出「这边交给我，你们先走吧！」，
一个人殿后对抗敌人大军，就在他终于消灭敌人回到城镇时，却发现时间已经过了十年！？而自己却莫名其妙成了救世英雄！？
勒库的新冒险旅程又将如何发展——

Luck, an S-rank mage in the hero’s party, makes a last stand against the Demon King to save his companions. When he finally returns victorious, ten years have passed, and the world praises him as a legendary hero who died in battle. Unable to reclaim his former life, Luck conceals his identity and begins again as “Lock,” an F-rank adventurer forging a future in a world that moved on without him.