Yako gets annoyed when her childhood friend, Kota, who insulted her flat chest when she tried changing in front of him. Haruka feels some tightness in her chest, which Mizuno deducing that she is starting to develop feelings towards Hiroki. As the girls head off to a summer festival, Kiyono explains to Yako that Kota felt hurt because he wasn't being registered as a member of the opposite sex...