My Brother’s Best Friend by Randi Rigby

I can’t stand him—he can’t stand me.
Neither one of us can stand her.
It’s an enemy love triangle.

Harper:
Cal might be my big brother by twelve minutes, but trust me, the boy needs looking after—he’s too sweet. I guess that makes me the evil twin. I just know I’ll do whatever it takes to protect him from the clutches of the new girl.
Including pretending to like his best friend, Luke Drake.
Luke might make me crazy, but when it comes to Cal, I know I have no greater ally. I’m just slightly weirded out by how easily his hand fits in mine.

Luke:
I met Cal Adams in third grade, and we were instant friends. But somehow, after surviving playground scraps together, voice changes, and the minefield that’s my home life; he became my brother. I’d die for the guy.
Or worse, I’d date his sister.
Harper is the most maddening girl you’ll ever meet. She might look like an angel but don’t be fooled—she’s not one to back down from a fight.
Cal can’t see his new crush is bad news. And while Harper and I can’t spend five minutes together without wanting to kill each other, she loves Cal fiercely, and I need that fire right now…even if I’m the one who ends up getting burned.