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.

Haruka invites Yuu to join her in attending a relative's wedding, which Yuu misinterprets as Haruka asking her to marry her. Although Yuu is disappointed that this is not the case, Haruka becomes touched by the thought of it. On Christmas Eve, Mitsuki joins Haruka and the others in visiting the Christmas lights, noticing that Haruka and Yuu seem to be shying away from each other. After Haruka and Yuu become separated from the others, Haruka reveals she had been shy to look Yuu in the face because of the strong feelings she's been having, with Yuu replying she had felt the same.