Kate Nolan is a successful magazine editor with a loving husband, James, and a five-year-old son, Max. Her life couldn't be more perfect—but one day she receives a phone call from James, which changes everything.

Clearly distressed, James tells Kate to meet him at midnight outside the beach café once owned by her long-dead grandmother in the seaside town of Seahaven, where they both grew up. A strange request, made even more sinister by the fact that in recent weeks Seahaven has become prey to a serial killer who is targeting the local children.

Kate keeps the midnight appointment, but instead of finding her husband and son, she finds herself drawn into an ever-tightening web of past misdeeds and long-buried secrets. As hopes for her missing family fade, Kate becomes involved in a desperate race against time. Where are her husband and son? Have they become the latest victims of the serial killer, who calls himself Dominic and seems to know her intimately? And what has all this to do with Kate's childhood terror of the impenetrable darkness known as "the black"?