Julia Bennett has worked hard to create a stable life for her daughter, Cora, in Southern California. So when Cora leaves for college, the worst thing Julia expects on move-in day is an argument with her ex-husband and his new wife. But a sudden attack leaves the campus stunned-and only Julia's quick actions save Cora's life. Shaken in the aftermath, and haunted by a dark secret, Julia starts to wonder: What if the attack wasn't as random as everyone believes?

Newly pregnant Ren Petrovic has an unusual career-she's a trained assassin, operating under a strict moral code. Ren wasn't on campus that day, but she knows who was: her husband, Nolan. What she doesn't know is why Nolan has broken their rules by not telling her about the job in advance. The more Ren looks into the attack, the more she begins to question: Who really hired Nolan? And why did one woman in the crowd respond so differently from all the rest?

Julia and Ren each want answers, but their searches quickly pit them against each other. One woman is a hired killer, but the other is a determined survivor. And both mothers will defend their families to the bitter end.