Yūto, Haruka, Mika and Nanami become increasingly worried about Hazuki's attempt to distance herself from the family and thus decide to follow her on a shopping trip, meeting up with various familiar faces like Yūto's otaku friend Nobunaga, Yūto's sister Ruko and their teacher Yukari. Mika and Nanami eventually becomes distracted in buying lingerie, leaving Yūto and Haruka to the job and almost came to a conclusion that Hazuki was about to get married and quit her job. Before going home, they had a misunderstanding with a bridal shop where they are thought to be customers and were given a chance to take a portrait together with Yūto wearing a tuxedo and Haruka in a wedding dress. That night, Hazuki, much to everyone's relief, explains that she is not quitting, but was just going to a hardware store, which was located above the bridal shop, to fix her chainsaw.

Yūto and Haruka attend the summer Comiket convention together, but since it is the first time for both of them, they underestimate the massive scale and hoards of people who attend. Mika, Hazuki, and Nanami tag along in disguise and help Haruka obtain a dōjinshi she wanted, and to get her out of trouble when people started taking pictures of her. Yūto and Haruka grow closer throughout the day, but after he leaves her at her house, Yūto is asked if he and Haruka were followed by anyone at the convention, but he says he did not see anyone like that. That night, a frantic Haruka unexpectedly shows up at Yūto's house.

Mika becomes angry when she realizes that the relationship between Yūto and her sister is not progressing as well as she expected, so she forces Yūto out on a date with her to teach him tips to get in the right mood with Haruka. During their date, they go to a café, and catch a movie before running into Shiina, which makes Mika jealous. Mika drags Yūto to a kimono shop and the two are outfitted with brand-new kimonos before heading to the summer festival and watching the fireworks with Haruka, Hazuki, and Nanami who find them. Once school starts again, Shiina volunteers to be one of the organizing members for her class' participation in the upcoming cultural festival, and Yūto gets dragged in to work with her.

Haruka quickly leaves after seeing Yūto on top of Shiina, but when Yūto tries to explain the situation to her, Haruka says she understands, but ends up running back home. The next day during the school festival, Yūto finds Haruka to have apparently forgotten about yesterday, though Shiina is not so sure. Yūto confronts Haruka about yesterday again, but she tells him she does not want to hear what he has to say and runs off. Yūto runs into Hazuki as he is searching for Haruka, and she gives him so advice on how to move forward with Haruka. With Hazuki's help, Yūto finds Haruka behind the gym where he apologizes for yesterday and assures her that he will not leave her. Afterwards, the two dance by the tune of the music box Yūto gave her previously as Nanami, Mika, and Hazuki watch from the bushes.