After slaying the demon king and facing persecution from the Kingdom, Blum Dilmond finds himself on the run from relentless assassins. Desperate to evade his pursuers, he devises a risky plan: seek refuge in the very dungeon once ruled by the fallen monarch. Venturing inside, he encounters an unexpected ally—a powerful mage residing deep within the labyrinth. To his surprise, he also crosses paths with Irene, a former maid of the Demon King who shares a common goal. United by a mutual interest, Blum, Irene, and the mage join forces to rebuild the dilapidated dungeon into a sanctuary, free from external threats. Together, they embark on a journey to transform the once-feared domain into a haven of safety and redemption.