Aikawa Sousuke is a part-time worker who lives in a run-down apartment where his only consolation is that the landlord is a beautiful woman and the girl who lives above him is cute. One day he hears a creaking sound from his ceiling, and suddenly the resident of the apartment above his, Sunao Unyuu, falls through a hole that appears in his ceiling onto his bed. Thus starts Sousuke and Sunao's comical life of living together.