Aoi lives in a small apartment alone as her parents live and work abroad. One day someone knocks on the door and she realizes it might be her new neighbor  coming to introduce himself. Aoi is shell-shocked when she realizes her neighbor is none other than Kuguyama.

Aoi's first attempt at being cold towards him soon fails. Kuguyama totally cannot cook, so she can't help but cook for him. He really enjoys her cooking and Aoi starts to think that he might not be such a bad guy after all. He is still the one who rejected her friend, but it probably isn't easy being a boy who is constantly approached by strange girls who even stalk him to his apartment.

Aoi decides to keep cooking for him, but one night she burns something in the pan, causing the emergency sprinkler system to activate and flood Kuguyama's apartment, making it temporarily uninhabitable. What is Kuguyama is supposed to do? Of course, he moves into Aoi's apartment, though she is reluctant at first. She can't let anyone, especially her best friend, know that she is living with that jerk. But how is their relationship as roommates going to work?