Rin, Yuu, Koyomi and Keita are childhood friends and are in the same high school. They all live in the same apartment building. Rin and Yuu like each other, but they don't tell each other how they feel. To hide his feelings for Yuu, Rin often makes biting remarks to her. Yuu doesn't know that Rin likes her and she isn't confident enough to tell him her feelings. Kazuma then appears in front of them. Based on the manga series "Ui Rabu -Uiuishii Koi no Ohanashi-" by Hoshimori Yukimo.