The day of the school festival has finally arrived. Natsuki is moved to tears when she receives a class T-shirt, something that wasn't provided before her time leap. Meanwhile, Shi invites Natsuki to tour the festival with her, saying she has something important to tell her. On the second day, it's finally Natsuki's band's turn to perform on the outdoor stage. Serika, Iwano, Naru, and Natsuki nod in agreement, determined to give the best performance possible, and the curtain rises on this "ragtag group of leftovers." Where will Natsuki's feelings lead her as she sings from this prime seat of youth?

With all the band members finally assembled, Natsuki and the others begin practicing in earnest. For their first song to perform at the school festival, they decide to jam to a song written and composed by Serika. During the performance, Natsuki feels the stark difference in skill between herself and the other members and loses confidence. However, Serika encourages her, saying she likes Natsuki's singing voice. A week after the band was formed, Serika, struggling to write lyrics for their second song, which is themed around "the past" and "regret," asks Natsuki to write the lyrics for her.

September arrived, and with summer vacation over, everyday life returned. Natsuki is invited by Serika to form a band together. Confused by the sudden offer, Natsuki initially tries to refuse, but realizing Serika's enthusiasm and her own desire to live a youth without regrets, she decides to join the band. The two immediately begin searching for other band members... Meanwhile, Hikari has made up her mind to confront her feelings for Natsuki.

One morning during summer vacation, Natsuki and her friends gather in front of Takasaki Station and set off for a beach in Niigata Prefecture. During the journey, Natsuki and Miori's classmate, Honjo Serika, bond over their shared love of music. Despite being swept up in Serika's unique pace, Natsuki's circle of friends expands. Upon arriving at the seaside town, the group enjoys swimming, a BBQ, and fireworks. It's the sparkling summer day that Natsuki had always dreamed of.

Suddenly, Natsuki receives a message from Hikarisaying she's nearby. Worried about Hikari, who says she ran away from home after an argument with her father, Natsuki reluctantly lets her into her house. Natsuki is nervous being alone in her room with the person she likes... Amidst this, Hikari confides in Natsuki about her relationship with her father, her past, and her dream of becoming a novelist. The next day, in order to gain her father's approval, she makes a certain decision.

Natsuki's friends plan an overnight trip, but Hikari may not be able to attend.

Natsuki convinces Miori to accept his help and attends a festival with Uta.

Natsuki, Miori, Reita, and Hikari go on a double date.

Without Tatsuya, Natsuki's once colorful adolescence slowly begins to darken.

Natsuki begins working at a café, and he and his friends study for midterm exams.

Natsuki hangs out with his new friends on the weekend.

Haibara Natsuki travels back in time and gets a second shot at a better high school experience.