Armed with a sassy haircut, a sharp wit, and a personal list of rules for all life's exigencies, Grace Santiago has everything under control. At least until Ethan Castle walks back into her life. Grace hasn't forgotten their disastrous affair in law school, but she can't resist his bad boy charm.

When Grace learns that Ethan has been hired by the other side, her loyalties—and her heart—are torn in two. Though their sexual chemistry can't be denied, they find themselves deadlocked. Ethan believes that all is fair in love and war, but he won't give up the fight—not even to win Grace's heart. So what can a good girl like Grace do, but learn to play dirty?