After an accident that nearly kills her, Emily and her husband, Freddie, move from London to a beautiful Dartmoor country house called Larkin Lodge. The house is gorgeous, striking—and to Emily, something about it feels deeply wrong. Old boards creak at night, fires go out, and books fall from the shelves, and all of it stems from the terrible presence she feels in the third-floor room. But these things happen only when Emily’s alone, so are they happening at all?

Marshall Miller would’ve remembered her face even if he hadn’t seen it on a MISSING poster. When a young woman disappears in his small town, the investigation hinges on Marshall’s haunted sighting of her, crying in the back seat of a police car driven by a cop named Maddox. There’s only one problem: no local cop named Maddox exists. But the speeding ticket he handed to Marshall certainly does.

1917. On a battlefield near the River Escaut, John lies in the aftermath of a blast, unable to move or feel his legs. Struggling to focus his thoughts, he is lost to memory as the snow falls—a chance encounter in a pub by a railway, a hot bath with his lover on a winter night. 1920. John has returned from war to North Yorkshire, near a different river. He is alive but still not whole. Reunited with Helena, an artist, he reopens his photography business and tries to keep on living. But the past erupts insistently into the present, as ghosts begin to surface in his pictures

In 1938, a dead whale washes up on the shores of remote Welsh island. For Manod, who has spent her whole life on the island, it feels like both a portent of doom and a symbol of what may lie beyond the island's shores. A young woman living with her father and her sister (to whom she has reluctantly but devotedly become a mother following the death of their own mother years prior), Manod can't shake her welling desire to explore life beyond the beautiful yet blisteringly harsh islands that her hardscrabble family has called home for generations.

Scientist Beth Darlow has discovered the unimaginable. She's built a machine that allows human consciousness to travel through time—to any point in the traveler's lifetime—and relive moments of their life. An impossible breakthrough, but it's not perfect: the traveler has no way to interact with the past. They can only observe. After Beth's husband, the co-creator of the machine, dies in a tragic car accident, Beth is left to raise daughter—and continue the work they started. Mired in grief and threatened by her CEO, Beth pushes herself to the limit to prove the value of her technology.