The Koizumi siblings have a father who is a professional violinist and a mother who is a professional pianist. Unlike her older brothers who have musical talent like their parents, Karin is a poor student at her music high school. She is proud of her twin brother Kazune, who is beginning to follow their father's footsteps into the professional violin world, but every so often, the seeming gap between them depresses her. This is a heartwarming story about the Koizumi family who love and support each other through tough times.