Tatsuko of class 5-1 is really excited about the upcoming school sports festival, her proposal for a new "Eel Scooping" event is less than enthusiastically received though, especially by Suzuka. Illya mentions the main event dance to Miyu, and as teacher Taiga Fujimura points out, it entails a huge reward, but will require quite a bit of practice.

And so the close friends: sarcastic Nanaki, level-headed Suzuka, excitable Tatsuko, energetic Illya, shy Mimi, and reserved but athletic Miyu are off to win the dance event for the honour of their class and for Fujimura, who seems to have some saucy bet going on that she most definitely needs to win, or so the girls misunderstand.

(Source: AniDB)