Bree Cabbat's life is perfect. She's got a loving, successful husband, two talented teenage daughters, a brand-new baby boy, and every opportunity in the world. When Bree wakes one morning and sees a strange woman staring through her bedroom window, she dismisses it as a fading dream, spawned by postpartum anxiety. But Bree soon realizes the nightmare is only beginning when her son goes missing. In his place is a note that tells her exactly what she must do if she wants him back. Until then, Bree is promised, her son will be safe in the hands of another mother. All Bree has to do is one, small thing—then her son will be returned and she can go back to her comfortable, uncomplicated life. But Bree’s actions come with a devastating price, making her complicit in an escalating web of dark secrets with deadly stakes that threaten to destroy everything she loves. Who is this other mother, and what does she want? Bree will do anything to protect her family—but what if the cost is tearing her family apart?