Ichijou Hotaru is enjoying life with her classmates at her new school. In particular, she has come to think of the diminutive Koshigaya Komari, at less than 140cm, as her “cute Senpai.” This feeling soon grows into absolute adoration. Then, one day, Komari calls Hotaru and invites her to hang out together…

With Kazuha absent at the start of the new semester, the girls try and find ways to pass the time in class. Later, Hotaru and Renge try and catch a rabbit that had escaped from its pen, only for it to lock them inside the pen themselves, though they are eventually rescued by Kazuha. Afterwards, Renge visits the candy store run by Kaede Kagayama, who finds her to be a handful.

Since the school doesn’t hold cultural festivals, Natsumi suggests they hold their own and invite the alumni, including Kaede, Konomi and Hikage. At the festival, the girls run a café, hold an art exhibit and put on a play. However, they’re play ends up being overwhelming and they end up slacking on food orders. They do eventually work together to prepare some food and have fun. Afterwards, Komari and Konomi help clean Natsumi’s room, where they find a lot of old toys.

After sleeping through the New Year, Renge joins Kazuha, Hikage and Kaede as they decide to go up a mountain to watch the first sunrise of the year. Along the way, Kaede recalls five years ago when she was first asked to look after the one-year-old Renge, initially finding her to be quite a handful but soon taking a liking to her. They eventually manage to reach the top of the mountain and watch the sun as it rises.

Due to a snowy blizzard, the girls end up having to spend the night at school, with Hotaru and Natsumi competing against each other to see who gets to sleep in a futon, eventually decided to just kick Kazuho out of hers. Later that night, Hotaru decides to check out the snow and see the starry night sky, leading to some misunderstandings from Komari and Natsumi. Later, on another snowy day, the gang decide to try their hand at skiing before building a snow house and having some hot food.

As Spring arrives again, Hotaru and Komari go on a picnic together, where Hotaru ends up eating Komari’s botched up homemade lunch in order to not hurt her feelings. Later, the girls get together to search for some edible plants, eventually coming to a field of renge flowers where Natsumi makes a costume for Renge.

An OVA bundled with the seventh manga volume.

Suguru wins some tickets to Okinawa in a shopping mall lottery, so the whole gang plan to go on a trip there. To prepare for the trip, the girls practice being on an airplane and go to a convenience store to buy some travel things. Meanwhile, Renge is very thoughtful about how the trip may change her view on the world, spending the evening before the trip giving her farewells to the countryside. The next day, everyone sets off on their flight to Okinawa.

When Renge receives a bike from her grandma, she’s eager to practice so she can ride everywhere with her friends. But the rainy season is in full swing, so she sets about making a teru-teru bouzu in hopes that the rain will stop. Meanwhile, Renge is on duty to take care of the tadpole shrimp she caught while playing in a field, and she grows very fond of them.

One morning, Natsumi uses a toy fortune dispenser to read Komari’s fortune, and tells it her, “bad luck: beware of water.” Komari says she won’t be near any water that day anyway, but when they get to school, they’re told that they’ll be cleaning the school pool… The next day, the Koshigaya sisters are bored at home on a day off from school, so Natsumi reads Komari’s fortune again and draws yet another “bad luck”…

The second semester has begun, and the Asahigaoka students are making wood crafts in class. Renge and Natsumi pair up to make something together, but can’t come up with any ideas. Just when Natsumi starts to panic, Renge demonstrates her unique sensibilities again. Then at lunchtime, the smell of curry fills the air, and the Koshigaya sisters recall a tragedy that befell the school long ago…

Natsumi’s mother asks Natsumi to go catch something to live in the family’s pond, and Natsumi agrees when she’s told she’ll be paid. She lends Natsumi a watch and tells her to be home by curfew, and all the kids go out for a day of fishing. Later, Konomi sees that Natsumi still doesn’t seem like a girl at all even now that she’s in middle school, and brings some of her old outfits over for her to try on…

Renge goes to visit Natsumi, but she and her family aren’t home. She’s about to give up and leave when a hand starts talking to her from the other side of the fence! She thinks it’s a monster, and is relieved to learn that it’s the next door neighbor Konomi. But Konomi then tells her that she is, in fact, a monster… Later, the Koshigaya sisters tell Renge they were in first grade when they took off their training wheels, so Renge starts to practice riding her bike without the training wheels.

One morning during winter break, Ichijo Hotaru and Koshigaya Komari are on a walk when they run into Fujimiya Konomi on her way back from practice. Komari takes great interest in Konomi’s cellphone.

During spring break, Renge and Hotaru head to school to feed the rabbits and end up finding Renge’s Legendary Sword.

An OVA bundled with the tenth manga volume.

On a Winter day, Hotaru has fun creating all kinds of things with the snow, which end up triggering a chain reaction of mishaps for Komari. During Spring, Hotaru goes to the candy store by herself and ends up making cookies with Kaede. On the last day of Summer, the girls use various senses to try and give Komari a pleasant dream. Finally, during the Autumn, the girls go to the woods to collect fruit, where Komari comes up against a flying squirrel.

Ren pays Candy Store a visit to spend her New Year’s allowance, but her purchase puts Candy Store in an awkward position — one Natsumi finds absolutely HILARIOUS.

Parents’ Day provides Natsumi a particular variety of anxiety, but she finds a way to relax when Renge brings home a new friend.

New Year’s is here, and that means New Year’s money! What will everyone spend their cash on? And is there a way to get even more? Or perhaps that’s not a good idea…

Once the kids are asleep, the adults get to partying! …wait, what’s that noise? Ren is awake!? Uh oh…

Following a graduation ceremony, Renge and friends spend the day playing in the great outdoors. It’s days like these you wish would never end…

An OVA bundled with the special edition of Atto's spin-off manga Non Non Biyori Remember.