When her mother remarries, Matsuri Amamiya (Meari Hayashi) becomes the younger stepsister to triplets who form the popular male idol group Terezetto. Matsuri always dreamed of having brothers, but she's dismayed to learn that the brothers don't get along. Azusa (Kazuto Mokudai), the middle sibling, wishes that he and his brothers were closer, so Matsuri decides to plan a welcome party to bring the two families together. Unfortunately, the triplets end up fighting again – until Matsuri unexpectedly collapses, and the siblings decide to call a truce. Matsuri is determined to intervene every time the brothers argue, which works to some extent... until one day, Azusa confesses his love for her! Complicating matters further, Matsuri reunites with her handsome childhood friend Subaru (Minato Matsui), and he's about to debut in a rival idol group. This drama was adapted from the manga "Netsuai Prince: Onii-chan wa Kimi ga Suki" by Madoka Seizuki.