Myself; Yourself

Before he leaves the town of Sakuranomori, Sana Hidaka has a party with his friends, Syusuke Wakatsuki, Nanaka Yatsuhiro, Aoi Oribe, and Syuri Watatsuki. They each give him going away presents, with Nanaka playing a half-completed song on her violin. Five years later, Sana returns to Sakuranomori, staying at an apartment owned by Aoi's parents. When he goes to school the next day, he recognizes two of his childhood friends: Syusuke and Syuri. But when Nanaka enters the classroom, Sana fails to recognize her. As a result, he is furiously slapped by Nanaka.

Sana mulls over Nanaka's reaction, and is elected the classroom representative along with Nanaka when Syusuke refused to be the classroom representative for another year. Nanaka still acts coldly towards Sana, leaving him lost in the library. When he returns to the classroom with the aid of Asami Hoshino, she looks jealously at him and Asami. Later, Sana and Nanaka coincidentally go to the music room, where Nanaka, sequestered in the teacher's office, overhears Sana playing the song she played to him on her violin the day he left. Touched, she says hello to him the following morning.

In order to repair Sana's and Nanaka's relationship, Syusuke and Syuri decide to go on a trip to a river that the five used to go to in their youth. Beforehand, Sana accidentally breaks Nanaka's mirror, and Nanaka is appreciative when Sana buys her a new one, but forlorn after learning that Sana bought one for Asami as well. After the group goes to the river, they swim at the spa, where Nanaka is embarrassed at her lackluster swimsuit. As Nanaka is going home with Sana and Aoi, she reveals she made cookies for the group, and the three eat them at Aoi's apartment. There, Sana gives Nanaka a pink stone he found near the river as a gift.