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…

Hotaru and Renge are invited to the Koshigaya’s house for breakfast. Afterwards, the girls, accompanied by Kazuha, go to the beach, where Komari’s height leads her to be mistaken for a lost child. On their way home, the girls stop at a railside noodle restaurant, where a prank by Natsumi on Komari backfires due to Renge’s innocence. They manage to catch the last train home on time, but accidentally leave Kazuha behind.

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.