This movie understands that swimming is just the excuse. What matters is watching Haruka and Makoto realize they need each other, that their friendship is the actual thing worth fighting for. The pacing drags in places, but when it lands, it lands on something real: two kids figuring out who they are by learning who they are to someone else. That's not character development. That's growing up on screen.

Haruka Nanase and Makoto Tachibana are starting middle school at Iwatobi, and growing up brings changes they have to adjust to. Makoto fits in easily and stays upbeat about swimming, but Haruka has trouble making friends and keeps away from the swim club because of old troubles with the sport. After an argument, they end up joining the swim team anyway, where they plan to swim the medley relay alongside Shiina Asahi and Kirishima Ikuya. The four have different goals, outlooks and baggage, so relay practice gets off to a rocky start. The film is a prequel adapted from the light novel High☆Speed!, mixing comedy and drama with slice of life sports as the boys work on their skills, bring their swimming styles into sync, and sort out mixed feelings about the pool and about one another.