[From StarryHeaven]:

Miyako loves Seiji, but he doesn't know. It's now Spring and the cherry blossoms are beginning to bloom. She's a boring, normal girl amongst an extremely unique family full of popular and hot siblings. If Seiji thinks that her clueless older sister Hijiri is so great, how is she supposed to confess her love to him? Seiji knows Miyako loves someone, so he says that they should keep their distant for a while, when suddenly she confesses to him! His reaction is not good; he leaves Miyako in tears...if she can't even talk to him normally, how are they supposed to work things out, especially if Seiji is meeting her older sister?

*Chapter 3 & 4 of Sora no Mannaka