Haruka Takayama and Yuu Sonoda are two best friends who are just starting high school together. However, as the school year starts and the two starting making new friends, Haruka worries that her friendship with Yuu will stop being special. After Yuu suggests that the two of them do something that is unique to them, Haruka suggests they start kissing each other in secret as proof of their special friendship. Later, Haruka and Yuu get locked inside an empty classroom whilst they were kissing on the veranda, requiring them to cross a large gap between verandas to get to the neighbouring classroom.

The girls decide to sleep over at school in order to complete their preparations for the cultural festival. During the nighttime, Shizuku gets to spend some time with Kotone, whillst Haruka and Yuu also have some time together. On the day of the festival, after a successful performance, Haruka goes around the festival with Kaede and Yuzu, where Kaede explains why she chose to become the class representative. Haruka and Yuu then spend the rest of the festival together, kissing all the while.

Kaede introduces Haruka and Yuu to Sumi Otokawa, who is to succeed Mitsuki as student council president, who asks for their help in deciding what to do for Mitsuki and student vice-president Rina Sakai for their graduation. The three of them decide to investigate the third years, finding them have a peculiar fondness for pudding, deciding on holding a 'bucket pudding contest'. After Sumi takes her leave, Mitsuki and Rina walk in on Haruka and Yuu kissing each other. Despite Mitsuki forbidding Haruka from kissing Yuu and having Kaede keep an eye on them, Haruka finds ways to sneak some kisses in during dance classes. Meanwhile, after speaking with Sumi, Mitsuki comes to the realization that she herself is in love with Haruka.