Mizuki Ryosuke escaped corporate life, certain death, defeated a Boss Ogre, and now lives with a new roommate—fairy girl Kessie! A dungeon appears in Omori City, and the local government asks him to help manage it. Mizuki reluctantly accepts, and with his skillbook in tow, the dungeon clearing proceeds as planned. When Mizuki and Kessie face their greatest trial yet, will the skillbook reveal its true form? And is there any truth to that weird conspiracy going around?