Yotsuba Hazama has it made. Summer vacation is just around the corner, and this year she gets to spend it with her two girlfriends, Yuna and Rinka! Sure, she'll spend it doing makeup lessons instead unless she passes all her finals, but how hard could that be? And her girlfriends' fan club is a ticking time bomb in the background of her school life, but it's not like that has any chance of causing her problems! And, yes, her little sisters have been treating her with an inexplicable mixture of contempt and suspicion lately, but there's no way that'll go anywhere unpleasant!
On second thought, let's start over: Yotsuba Hazama is in way over her head! Her first-ever summer with her new girlfriends is in peril of flunking-induced cancellation, her social standing at school is dangling by a thread, and she can't even figure out what's wrong with her relationship with her sisters, but it's definitely going to be a problem! Who knew having two girlfriends could be this difficult?!