The book opens with a prologue by a young woman, who is filming herself as she refers to some kind of domestic abuse, before the her mobile ‘phone goes dead. Obviously she is, too. The chapters cover events from the day before, which is the 23 December, and go forward from there. It sets the scene and introduces the characters, the central one being an ex-detective police officer on her way to Fort William in Scotland, for the birth of her daughter’s child.

The story is primarily told from point of view of the detective, with frequent flashbacks to a traumatic event in her past. The first half is quite slow as the situation unfurls and is full of snow themed similes that come across as humour but definitely add to the wintery atmosphere. In the second half of the book the pace increases along with the suspicions and tension. The ending is a tad confusing and disappointing though.

An enjoyable read although there are some dark themes that include coercive control and sexual assault. A few parts stretch credulity a bit, but the overall feel of the story is of a locked room mystery with an amazing snowy background. Love the idea of travelling to Fort William by train for Christmas. As long as there are no killers on board, obviously.