In a world where dungeons appear and skilled players battle for glory, Yukari Kanzaki dreams of clearing the legendary Luluheart Dungeon. Branded “powerless,” he is denied even the chance to enter. But when a Dungeon Break unleashes monsters into the world, Yukari saves an injured girl—only to discover she is Luluheart, the Demon Lord herself. Granted a chance to save the world, Yukari returns six years into the past, armed with the ability to regress through death.