In Emma Rowley's emotionally gripping, unpredictable novel of psychological suspense, a mother who works at a charity helpline for missing teens receives a desperate call—from her own daughter...

The missing don't always want to be found.

Kate Harlow recognizes this painful truth, even as she keeps searching for her daughter, Sophie, who disappeared two years ago. The police have stopped investigating—after all, Sophie has sent postcards home, insisting that she's fine. To fill the space in her increasingly empty days, Kate volunteers at Message in a Bottle, where runaways can leave messages for loved ones, no questions asked.

Then one evening, a call comes in from a voice Kate instinctively recognizes, even through bursts of static and beyond the sudden dial tone that breaks their connection.

Those closest to Kate worry she's cracking under her grief, imagining that it was Sophie. But Kate knows—that it was...