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.

On a snowy day, Haruka and Shizuku go outside to have their lunch, though soon find it a bit too cold. As Shizuku dreads the day when she'll have to part ways with Kotone, Haruka brings Kotone over to cheer her up, encouraging everyone else to come out for a snowball fight. Meanwhile, Kaede mentions to Mitsuki how she believes Haruka and Yuu are dating. Later during gym, Haruka feels the need to compete against Kaede in jumprope, only for her group to end up coming last and having to clear up the equipment. As Haruka offers to do it alone and the others leave, the teacher assumes they were finished and ends up locking Haruka in the gym storage. Learning of Haruka's disappearance, the girls set up a ladder to the gym storage's window, where Yuu manages to get a kiss with Haruka, before they manage to get the door unlocked.