Now that he enters his high-school career, Satomi Koutaro begins his life living alone in an apartment that only costs him 5000 yen per month, an extremely cheap deal even for this small apartment. There's a catch: the apartment is apparently haunted by a cute ghost that has driven its prior occupants away. Next thing he knows, not only is there a ghost trying to drive him out of his new home, but magical girls and other unique female characters turn this small apartment into a battleground of sorts.