Yukino and Kanade Sakurai are twin sisters that live together in a high school dorm. Although they are twins, they tend to act romantic toward each other, holding hands and going on dates. One day, Kanade sees Yukino hanging out with a new girl, Sakuya Kamiyama. Realizing how much time these two spend together, Kanade assumes they are dating, and she begins to distance herself from her sister. Yukino promptly notices and pleads with Kanade not to leave. In reality, Sakuya has only been asking for advice about Kanade, revealing her obsessive love. How will this love triangle play out?
Episodes
Remembering the times when she and Yukino used to walk under an umbrella together, Kanade works out a plan to relive those moments. A rainy day comes, but Kanade is unable to find her umbrella. Luckily Yukino also remembered those days and brought her own.
In the run up to Christmas, Kanade and Yukino look for presents for each other. Meanwhile, Sakuya makes plans for the new dorms being built. Kanade finds a perfect, albeit rather expensive, gift, using their plane ticket money in the process. While wondering how to get home, Sakuya shows up with airplane tickets, including one for herself.
Kanade and Yukino, along with Sakuya, arrive home where their younger sister, Shizuku, awaits them. While putting up with Sakuya, Kanade and Yukino learn that Shizuku has been jealous of the two's closeness.
Kanade and Yukino have to deal with the way things have turned out, while Shizuku has a talk with Sakuya, who explains why she fell for Kanade. Shizuku then spends the night with Kanade and Yukino and apologizes.
Kanade has a weird dream involving Yukino. While worrying about her exams and homework, she gets taken out by Yukino to a cafe for Valentine's Day. However, Kanade has to redo her homework for incorporating her dreams into them.
Kanade gets a stern lecture from her teacher concerning her recent art fumble, and Yukino warns her to be more careful. The new dorms are in preparations and Sakuya has a whole floor dedicated to her and Kanade, but then Kanade points out she already signed up to share one with Yukino and she freezes up. Kanade mentions that she might take extra classes during the Spring holidays, and has to tell Shizuku that they might not be home, which ruins plans she had. Yukino says that she'll get a part time job so Kanade can go to prep school, which stuns her a little.
Kanade is feeling both guilty that Yukino is doing a part time job for her sake, and lonely since she doesn't get to spend as much time with her. They are both surprised to find Shizuku at their apartment, who stays over. Sakuya tells Kanade that she should go apologize to Yukino, with Shizuku making a similar suggestion. Kanade later meets up with Yukino to apologize, telling her she'll take a short-term course instead of full term, and they promise to stay together forever. Yukino asks Kanade to get some cream off her mouth, which, to Yukino's surprise, Kanade removes with her lips. They later say that they love each other.
