College student Kanna suddenly finds herself with a new stepbrother due to her parent's remarriage, and she's been trying to adapt to her new family life. Even after a week, they've had limited chances to talk. However, Kanna decides to take the initiative. Though she gave off the impression of being serious and shy, she surprises everyone with her bold actions—actions that begin to reveal her true nature. The evolving relationship between her and her stepbrother promises an intense and captivating development.