Kat Caruso wishes her brain had a return policy, or at least a complaint hotline. The defective organ is constantly distracted, terrible at statistics, and absolutely flooded with inappropriate thoughts about her boyfriend's gorgeous best friend, Alec . . . who just so happens to be her brand-new math tutor. Who knew nerds could be so hot?

Kat usually goes through tutors like she does boyfriends—both always seem to bail when they realize how hopeless she is. It's safer for her heart to keep everyone at arm's length. But Alec is always stepping just a little too close.

Alec Stone should not be fantasizing about Kat. She's adorable, unbelievably witty, and completely off-limits. He'd never stab his best friend in the back . . .

But when secrets are revealed, the lines of loyalty are blurred. To make it count, Alec must learn that messy human emotions can't be solved like a trigonometry function. And Kat has to trust that he may be the first guy to want her for who she is, and not in spite of it.