High school freshman Koutarou Satomi finds Corona House Room 106, a spacious apartment renting for an implausible 5,000 yen a month, until he learns why it is so cheap. A ghost named Sanae Higashihongan already haunts the room and is set on driving him out. Within days a self-styled magical girl, an alien princess, and a girl from an underground civilization each turn up to claim it for their own reasons. This manga adapts the light novel series of the same name.