Metamorphosis of the Soul! (S03E08)

After the breakup of his middle school swim team, Ikuya decided to get stronger on his own and not rely on anyone. But then Haruka, breaking out of his freestyle comfort zone to swim in the individual medley, tells Ikuya, "You're not alone." As the two race side by side, Ikuya hears the sound of Haruka swimming, and suddenly he feels something in him changing... (Crunchyroll)