"Wherever I go, there are only people who know me. There is a reason why I couldn't know my brother. " Wooyoung took a swimming class in the summer semester for graduation. Taekyung, a member of a popular boy group who takes the same class, becomes a pair. Wooyoung guided Tae-kyung, who can't swim, and we became close. On the last day of the seasonal semester, Taekyung invites Wooyoung to his home. He reveals the reason why Taekyung chose Wooyoung as a pair through a deep story they shared while he was drunk...