I KISSED MY GIRLFRIENDS LITTLE SISTER LN VOL 01

It's been a month since I've started dating Haruka, my first ever girlfriend. We even finally reached first base today-holding hands! Today's also special for a different reason-my dad's getting remarried, which means I get a new stepsister. Her name is Shigure, and she's pretty much the spitting image of Haruka. That's no surprise though, given that she's actually Haruka's long-lost twin sister! Due to family circumstances, they were split up at birth. Her presence adds a new, twisted form of love that tangles itself into our protagonist's passionate love life! He can't possibly tell his girlfriend what's been going on!