On Oriyama Karin’s 16th birthday, she receives a present from her rich parents. Her present is marriage. The person she marries is her crush and high school senior Tsurugi Nao who is popular. Debt ridden Nao only marries Karin for economic reasons and in particular the wealth of her parents. Karin loves him truly, but Nao doesn't love her at all. Their marriage is a secret, but Ebina Isuzu, Karin's friend, holds feelings for Karin, learns of their marriage. Adapted from a manga of the same name by Minami Kanan (水波風南).