At first glance, Konoha Koga is an average high school girl who lives alone. However, she has a secret—she works as an assassin on the side! One day, fate puts her in an encounter with Satoko Kusagukare, a runaway ninja hunted by her comrades for accidentally leaving her village.

When Konoha kills one of the people seeking Satoko, the mysterious girl uses her exceptional ability to cover up corpses. Seeing potential in Satoko's skill, Konoha offers her a deal: she can live with Konoha in exchange for cleaning up the scenes of her assassinations. As the ninja and the assassin now live under one roof, they begin enjoying their new life together, whether at home or during their conveniently aligned collaborations.