Recently widowed Agnes Lockwood is spending a few days on Tyneside in Northeast England, catching up with her past. When expensive jewelry is stolen at the hotel, Chief Inspector Alan Johnson gets on the case. After Alan recognizes Agnes as a friend from schooldays, they rekindle their friendship and Agnes bombards him with questions about the case. But after dinner one evening, they find a body lying on the roadside. Fearing for her safety, Alan warns Agnes to stay away from the case. But being an inquisitive woman, Agnes cannot resist getting involved...too involved.

When Detective Madison Harper arrives at a remote summer camp in Shadow Falls, Northern California, her heart breaks for Jenny, the sweet little girl last seen splashing in the lake with her friends before she vanished. Peering into the silent cabins filled with rows of neatly made beds, Madison knows this idyllic place is hiding a terrible secret.

Criminologist Martin Knight lives a gilded life and is a thorn in the side of the police. But then his wife, Liz, goes missing. There is no good explanation and no sign of Martin.... To make things worse, Liz is the ex-girlfriend of DCI Craig Gillard who is drawn into the investigation. Is it just a missing person or something worse? And what relevance do the events around the shocking Girl F case, so taken up by Knight, have to do with the present? The truth is darker than you could ever have imagined.

Harley, reeling from her being put on leave, from her long-term relationship falling apart, and from her father’s dying, is hardly ready to return to her hometown, to its long-buried secrets, and her tortured past. She spent her life escaping this small town—but, as she settles back in, she wonders: Might she have been wrong all this time? Yet as more bodies surface and as every clue leads to a dead end, Harley, clashing with her new partner, realizes she’s in a race against time.

FBI Special Agent Faith Bold, hospitalized and haunted by her encounter with a serial killer, is ready to retire—when Turk, a K9 German shepherd, himself traumatized, comes into her life. When a new serial killer strikes, leaving his victims at the bottom of isolated wells, Faith, this time with Turk at her side, will stop at nothing to hunt him down and save the next victim before it is too late.