Shinjuku at night is not a safe place. Therefore, young college hopeful Tomoe Tatsumi lucks out by bumping into Mitsugu Kurokawa, a white-collar worker with a heart of gold. Charmed by Tatsumi's naivete, Kurokawa actually finds himself being more generous than usual. In the course of helping Tomoe-kun find a place to live in Tokyo, Kurokawa offers to rent out his extra room. And thus, the two of them come to live together... but it's not the situation that Kurokawa had hoped it would be! How long can Kurokawa keep from betraying Tatsumi's trust? Does Tatsumi's paranoid older brother really consider murder a viable option?