Amanchu!

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 try on some drysuits and take a dip in the pool. Moved by Hikari's high spirits, Futaba decides to join her in diving.

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 pressure and ear equalization.

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.

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 out to be their upperclassmen in the Diving Club. After a hectic first meeting, Ai holds a meeting to discuss how Futaba will be aiming for an Open Water Diver Certification, which somehow ends in a chalk drawing session.

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 lesson, Mato takes Futaba and Hikari on a drive, where Futaba thanks Hikari for helping her find her own wish.

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 hot day, Mato has the club play red light green light as punishment for skipping on their exam studies.

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 fitness exams, Hikari helps Futaba improve her self-confidence during the 1000m run.

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 Tokyo. As Futaba finds herself unable to delete any of her old photos to make room for new memories, Hikari and the others buy her a digital photo frame to store all of her photos, both old and new.

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 since meeting Hikari. Futaba expresses her concerns about whether she can become a suitable buddy for Hikari, though Hikari expresses that she's had times when she lost her way as well, saying that it is a chance to have more fun. Afterwards, Futaba finally manages to pass the pool course, allowing her to move on to the Open Diver course with everyone.