Jennie Townsend is unlucky in love, so she is immediately suspicious when a mysterious new student named Nate tries to gain her friendship. But there is something special about Nate, and in spite of her best efforts Jennie finds her feelings for the boy growing deeper every day.

In fact, Nate is more special than Jennie can even imagine. He is a guardian angel, sent to protect Jennie during a most dangerous time in her life. To do so, he must first become close to her – but not too close. The rules for Protectors warn against physical contact and strictly forbid falling in love. But the more time Nate spends with Jennie, the harder the rules are to follow. Will Nate be able to save Jennie from a premature end, or will his own emotions – and Jennie's – get in the way of completing the task for which he was specifically chosen?