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.

A legendary warrior stands alone against an overwhelming horde of darkness for ten grueling years, holding the line to protect a fragile world. Through sheer grit and unyielding willpower, this relentless defender turns an impossible siege into an enduring myth of supreme endurance. When the dust finally settles, the survivor transcends mortal limits to become a living legend whispered across generations.