In a hot summer day, after receiving a watermelon from the Hidamari landlady, Yuno and her friends make a visit to a local swimming pool, where Yuno's inability to swim and fear of water is revealed. Meanwhile, Yoshinoya, the Hidamari landlady, and the Principal spend their time together in a school swimming pool.

To Yuno, Miyako, and Sae's surprise, Hiro receives a love letter from a 3rd grade classmate. After hearing the news, Hiro's friends can hardly concentrate on the class as they are very curious about the love letter. After school is over, the classmate who write the love letter confesses his love for Hiro on the rooftop. However, on the next day, she writes him a letter of refusal, to everyone's disappointment. However, Hiro's friends look up to her for her maturity.

Sae buys a second-hand Polaroid camera and the four girls take pictures of each other dressing up and posing in different ways. Later Yuno calls Chika and arranges for her to visit Hidamari Apartments on March 25th, as seen in episode five of the second series. In the very brief second episode set the morning after, Yuno, Sae and Miyako wake up to discover a picture of their sleeping faces beside them on their pillows. This is Hiro's revenge for them laughing at the picture Sae took of her sleeping the day before.

Yuno receives a bike from one of her classmates but can't remember how to ride it. The girls decide to take the bike down to the riverbed to teach Yuno how to ride again.

Yuno stops Miyako from falling down the stairs at the apartments, but tears her uniform in the process. Yoshinoya-sensei notices and invites the girls to her room after class to fix it. The next day, having lost her Sketchbook somewhere, Yuno tells Sae and Hiro about the incident with Miyako's dress and what happened when they were invited into Yoshinoya-sensei's "forbidden room"...

June 11th: After receiving some coupons in their mailboxes, the girls decide to check out the opening of a family restaurant. To their surprise, they find the landlady is working there. April 7th-17th: On her first day of school, Natsume has a tough time, as her train gets delayed and she has trouble finding her shoe locker. This is where she first meets Sae and becomes instantly smitten with her. However, she has trouble trying to run into Sae throughout the week. She eventually spots her, but is shocked to see she is already close friends with Hiro, which explains her antagonistic attitude towards Sae.

June 23rd-25th: A bout of homesickness drives Yuno to pay a short visit to her parents' home, where she catches up on the lives of the friends she left behind. July 30th: Miyako finds an old barbecue and plans a cook-out in the back garden of Hidamari Apartments. While out buying charcoal for the barbecue, Sae and Hiro bump into Natsume and invite her along. That afternoon, she and Miss Yoshinoya join the residents of Hidamari Apartments at their barbecue. Having finally got the opportunity to spend some time together, Natsume overcomes her hostility towards Sae.

July 15th: During an exam break, the girls decide to go to an art museum to look at the artwork. August 28th: Whilst Sae and Hiro are busy with a study session, the rest of the girls go to the pool to practise swimming. Later, Hiro hosts a pajama party for everyone.

May 9th: Hiro and Sae decide to clean their curtains using Miyako's pool. May 25th: The Landlady treats the girls to an all you can eat Barbeque.

The Hidamari residents give Sae and Hiro their support as they take their college exams.

In the run up to graduation, Sae and Hiro tell the others about how they first met upon first moving into the Hidamari Apartments. Graduation day soon arrives, with many tears shed.