Jane Trevally is walking her dogs on her country estate when a small white terrier appears, alone and with no sign of the teenage girl he’d been staying with nearby. When the teenager is reported missing, Jane offers to return the dog to his registered owner, hours away in London. Arriving at a run-down house called Thornwood in the deepest backwaters of Hampstead, she is immediately on alert --- because Jane has a dark history with this house. The man who answers the door is not the man Jane remembers from her past. Then, through the window of the house, Jane catches a glimpse of a haunted-looking woman. Conjuring her memories from 25 years ago, Jane knows this unsettling house holds the key --- to the missing teenager, to her own traumatic story, and to the dark secrets of the past.