L-DK is manga by Ayu Watanabe. It’s have been adapted to Live Action film that was released Apr 2014.
Aoi Nishimori’s (Ayame Gouriki) 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. Shuusei Kugayama (Kento Yamazaki) is a prince in his high school and has a reputation of turning down confessions from admiring girls and one of them is Aoi’s friends Moe’s. And Shuusei just moved in next to Aoi's apartment. Due to a mistake, Aoi makes the sprinkler go off in his room. Until Shuusei’s room is fixed, he stays with Aoi.