For some reason, the daughter of the company president, Toiwa, is forced to live in an apartment building exclusively for criminals, and she moves in as the legendary assassin “Skull” in accordance with her parents' instructions. However, as soon as she moves in, she meets the real “Skull”, Hajime Koga, and suddenly her life is in danger. In an apartment where any kind of crime is forbidden, a never-ending game of “hide-and-seek” unfolds between Hajime and the real “Skull."