Follow the story of the Osaki sibling, with Yuu and her twin brother, Jun and Takeru who are constandly fighting with each other. The story is divided into 2 parts:

The first half of the story is about Jun and Takeru, who are now dislike Yuu's boy friend, Igarshi very much. They dislike him but when they are in front of Yuu, they tries not to bother her and have to try to pretend to be nice to him. Igarashi doesn't help either, he's aloof, doesn't care about the twin, and with his no sugar coating's sharp tongue, he often criticizing the twin for their silly behavior. This lead to a bigger problem because Jun and Takeru are now repressing their angst toward Igarashi and take it against each other instead, which is counter productive because it's still trouble Yuu for this anyway.

The 2nd part is about Yuu has a date with Igarashi, while Jun and Takeru got a free ticket to the theme park. Without knowing, it's the same place Yuu and Igarashi's dating right now. Before they meet and start a fight again, they got involves in the kidnapping case involuntarily. Igarashi is snatched and is held back after he accidentally witnesses the kidnapper talking with the hostage and on the other side of the themepark, The twin got their bag mixed up with the kidnapper's bag. How is this mess resolves.