Aoi Nishimori and Shusei Kugayama are in love and they begin to live together secretly. Suddenly, Shusei's cousin Reon Kugayama comes to them. Their secret is discovered by Reon. Now, Aoi, Shusei and Reon begin to live together.
Aoi Nishimori's parents moved to another city for work, but Aoi didn't want to transfer to a new high school. She stays behind and lives in an apartment by herself. Shusei Kugayama moves in next to Aoi's apartment. Shusei is a very popular student at their high school. Due to a mistake, Aoi makes the sprinkler go off in his room. Until Shusei's room is fixed, he stays with Aoi.