The Missing One, by Lucy Atkins

Set in the far reaches of a distant speck of an island off Seattle, this book will grip you from the very start.

After the death of her mother, Kali discovers a batch of postcards written by the same woman on the same day and posted every year. Yet her mother had never mentioned a "Susanna". Who was she?

After a bit of Googling (what did we do without it?), she traces Susanna as a gallery owner in the far-flung outposts of Canada.

Without stopping to think too much, Kali jumps on a plane with her small son, Finn. The trials of long-haul travel with a toddler is brilliantly conveyed, as is the atmospheric island. Kali has time to reflect on what she has so rashly done, by blowing the joint savings of her (and, she suspects, of her erring partner) on an air ticket to the middle of nowhere with a fractious toddler. But, it's too late. She's nearly there.

The hired car and the pre-booked BandB are a series of disasters and - at night, in thick fog - Kali arrives at the gallery of the mysterious Susanna, who seemed to play such a large part in her mother's life. She is unexpected, uninvited, and - it seems - most definitely not welcome.

Susanna is a creature that you won't forget in a hurry. Tall, bare-footed, seemingly impervious to the biting cold, with pale eyes like a wolf, she is the stuff of nightmares.

Brilliantly chilling.