Make Me Believe by Kate J. Blake

Sky:
He’s bold, bossy, arrogant, and always gets what he wants. When he saw me for the first time, he said that my lips were made for bl*w jobs. Who in the world tells a girl that on their first meeting? Zac Harden, that’s who. He’s my new stepbrother, an athlete with abs and a smile that most people would kill for.
I hate him. I literally hate him. But even more, I hate myself for thinking about him while reading those romance books that I hide under my bed…
But it doesn’t mean anything, right? No matter how many girls throw themselves at his feet, I will never let him have me.
Will I?

Zac:
The moment I saw her walk into the room to meet me, I already knew that this girl would be mine. She doesn’t want to admit it though, even to herself. She still thinks she’ll go to college one day and get rid of me.
Well, she’s wrong, so wrong. The second we move out of our parents’ house, I’m claiming her, taking everything she can give me and giving her everything I have in return.
How fortunate it is for me to find out that our parents are going on vacation without waiting until we go to college. They’re going to leave us alone together for the whole two weeks.
Would I be able to stay away from my step-sister? And, moreover, would she let me come closer if I’d want to?