The girl I like is my biogical sister?!

A highschool student name Yamazaki Megat was a shy and timid boy in his class. He has a crush name Tsunokami Watame but little does he know, his crush also likes him. but the thing is after he found out that she was his biogical sister, Megat doesn't know how to react but he still have a feelings for her So what will he going to do? Let's find out and go read it!