Koto, an adventurer who lives a lonely life, meets Milly, a girl who is a healer and was kicked out of the party for being useless. She had intended to ignore her, but for some reason she ended up taking her home with her, and not only did she end up living in her house...! The clumsy co-living fantasy in another world, where the strongest solitary adventurer and a clumsy healer challenge a dungeon, has begun!