Free! S01

The story of this anime is about a boy named Nanase Haruka who has always loved water and swimming. Before graduating from elementary school, he joins the school's swim team and participates in competitions with three of his teammates, Tachibana Makoto, Hazuki Nagisa, and Matsuka Rin. They win the competition and after that, each of them goes their separate ways. Time passes and they enter high school. One day, Rin appears in front of Haruka and invites him to a competition. Haruka loses and when he sees Rin's incredible power, he leaves and finds his old friends again, and also brings a new member named Ryugazaki Rei to the swim team, forming the Iwatobi school swim team with the goal of defeating Rin.