Futaba Ooki, a shy girl who had just moved from Tokyo to the beachside town of Shizuoka, catches the eye of her eccentric classmate, Hikari Kohinata, who instantly befriends her.

On her way to school, Hikari races against her homeroom teacher, Mato Katori, who she discovers to be a fellow scuba diver. Later that day, Hikari drags Futaba to the school's Diving Club, where they …

Hikari leads Futaba to a road filled with cherry blossom trees to cheer her up. The next day, Hikari and Futaba sign up for the Diving Club, where Mato, the club's advisor, teaches Futaba about air pr…

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 …

Noticing Futaba struggling with strength, Mato has her and Hikari go jogging to build up strength. Along the way, they come across some students from diving school, Ai and Makoto Ninomiya, who turn ou…

Futaba undergoes a pool course at the indoor pool, managing to properly learn how to clear her mask. However, it soon becomes apparent that Futaba doesn't actually know how to swim. Following the less…

On a rainy day, Mato decides to follow Hikari as she boards a train, discovering that her only reason for doing so was to witness some blooming hydrangeas for a brief instant. Later, on a particularly…

Makoto becomes concerned when Ai receives what appears to be a love letter from her classmate, only to later find it was addressed to another girl. Later, as Futaba and Hikari take part in various fit…

Futaba, who always takes photos to remember each moment, becomes shocked when her phone's memory has become full, requiring her to delete or move her old photos, including those of her friends from To…

Futaba and Hikari invite Ai to hang out with them as they go shopping for logbooks and swimsuits. Afterwards, the girls go to the beach, where Futaba tells Kino about all the things she has learned si…

Futaba and Hikari follow the club's mascot, Cha, leading them to take a path that neither of them has been down before. Along the way, they come across a small kitten that appears to have been separat…

The Open Diver course begins, with Futaba and Hikari paired up as buddies. Futaba loses one of her fins on the way to the descent point, but it gets picked up by another diver, turning her fears of th…

After helping out at Kino's beach house during a lunch rush, Futaba decides to return there the next day while Hikari goes scuba diving with the others. While there, Hikari accidentally goes into an o…

While Futaba is away for a memorial at her country home, Hikari befriends a girl by the sea who is fascinated by a mother octopus guarding her young - Futaba is determined to befriend her. Meanwhile, …

Futaba takes the underwater navigation tutorial but is brought crashing back to reality by the realization that she may be holding Hikari back - but is able to successfully complete it after she remem…

Futaba and Hikari spend an autumn day apart, and they both find autumn wonders of their own.

Futaba goes diving in a drysuit, as the gang looks to encounter the legendary Jet-Black Mermaid.

It's Halloween, and the Diving Club members find themselves in the midst of a special event in an amusement park. Hikari's in danger, and it's up to Futaba to be her knight in shining armor?

The Yumegaoka High Dream Festival arrives, and the night before, the entire student body is busy preparing for opening day. This night would end up becoming a very special one for Ai in particular, as…

After meeting Peter in an encounter straight out of fantasy, Ai now gets transported to a fantasy world, where she meets someone she never expected to meet.

Ai can't accept how Peter parted with Mato-chan and her, and so she decides to head back to Neverland, only this time she has company.

Teko is invited to bring in the new year at Amanchu-ya, and she finds herself in the company of the whole gang plus a few extras. As they watch the first sunrise, a new kind of emotion takes over her …

Pikari ends up with a cold on her birthday, so Teko decides to visit her at home. She finds someone on the way, which leads to plans for another fun event once Pikari recovers.

It's finally time for Teko's advanced certification test, with a promise of a night-diving celebration if she passes!