Futaba comes to observe a scuba diving class run by Hikari's grandmother, Kino. The next day, Futaba has her first experience diving in the school's pool, struggling to keep water out of her eye mask and losing confidence. However, with Hikari's guiding her as her buddy, she begins to get used to being underwater, managing to go to the deepest parts of the pool.
다이빙을 견학하러 온 테코는 피카리, 할머니, 그리고 새로운 사람들을 지켜보며 어서 잠수하고 싶다는 생각에 두근거린다. 그러나 수영장에서조차 마스크에 물이 계속해서 들어오는 등, 제대로 숨을 쉴 수가 없는데…
