Patterson Blake is an FBI Agent on a mission. When she was a teenager, her older sister vanished while on a cross-country road trip and hasn't been seen since. Patterson thought she'd put the trauma of her sister's disappearance behind her, but now there is new evidence, and suddenly the old wounds reopen. Except that Patterson isn't a kid anymore. She has a badge and a gun, and the resources to follow her sister's trail. But it won't be as easy as Patterson thinks.

She wakes on the shore of a remote lake in the middle of the night, freezing and afraid. With no memory of who she is or how she got there, she stumbles frantically toward the lights of a house. The handsome stranger who lives there is shocked to see a woman on his doorstep and takes her in. Trapped by a winter storm and cut off from the outside world, she starts to suspect that all is not right with the house on Gravewater Lake—or the man, who says his name is Gregg.

Blake Wilder is plagued with nightmares from her dark and twisted past. Fourteen years ago, her entire family was taken from her. Her parents murdered and her sister taken. At the age of 22, Blake joined the FBI in hopes of one day discovering the truth behind the mysteries of her own past.

Five years ago, Tessa Chamberlain was the lone survivor of a beach house massacre that left three of her friends dead—and Tessa with an inescapable, unending dread. Now she’s going back to face her fears. Renting the same beach house where she almost died, Tessa returns to lonely Cassadaga Island off the coast of Maine long after the tourists and summer residents have departed for the winter. But as the fog rolls in and the nights grow longer, she wonders if she made a terrible mistake. There are footsteps on the porch, creaks from the second floor, and an unsettling feeling of being watched.

On prom night, Caroline Winterfield walked away from the ruins of an abandoned mansion called Haven Cliff and into the woods…never to be seen again. Only her three best friends know what really happened. But a secret is a secret, and a promise is a promise—even when it shatters lifelong friendships. On the twenty-fifth anniversary of that night, Midge, Kelly, and Talia reunite at Haven Cliff, now a gleaming architectural jewel. But they aren’t alone. Someone is watching.