I Fell In Love With My Brother's Best Friend

Cassie.
She was sent off to a rehab in Missouri, for six months. She came back happy and heathy. Her brother Sam is the closest thing she has other than Ashton.
Sam has a new best friend since Cassie left. And let's just say he's a complete player.
He goes by the Name Mason Bartley 19 brown hair and absolutely gorgeous.
She has a hard time with him always trying to.
"Get in her pants" we might say.
Will she fall for his player ways? What will Sam do to Mason if she does?