Renting Corona House Room 106 for an unbelievable 5,000 yen a month, freshman Koutarou Satomi quickly learns the catch: the room already has a resident ghost, Sanae Higashihongan, and no shortage of newcomers competing for it. An alien princess, an underground dweller, and a magical girl each stake their own claim over the following volumes, drawing Koutarou into an escalating cohabitation rather than a fight for sole ownership. This ongoing light novel series is the original source material behind the manga and anime adaptations, running far longer than either.