A kunoichi who can kill demons with one hand while speedrunning gacha games with the other moves in, and the show understands that the joke is her complete lack of shame about it. Tsukasa gets dragged into the most absurd domestic situations because Shizuri treats her master-servant contract like a rental agreement where she pays rent in sarcasm. The comedy lands because nobody in this show pretends the setup is anything other than what it is: a lazy genius living rent-free, and the guy stuck feeding her while she ignores actual danger to hit a gacha pity timer.

Tsukasa Atsumi is an ordinary salaryman living a quiet, solitary life until a demon attacks him on his way home from work and a woman in ninja garb saves him. She is Shizuri Ideura, a gifted kunoichi, and she explains that demons hunt people with Samurai Blood like his. With the attacks set to grow more frequent, she agrees to guard him under a master-servant contract on the condition that she lives with him. The catch: when she is off duty, Shizuri is an otaku NEET who does little but play video games, and Tsukasa ends up spoiling her through a lazy life under one roof. Soon other eccentric kunoichi gather around them. The result is an ecchi romantic comedy about cohabitation, where Tsukasa comes to value Shizuri's company and she may feel the same way.