Discover the twisty, gripping I See You - a Richard & Judy Book Club pick and a Sunday Times Number One bestseller. And don't miss the next nail-biting thriller from Clare Mackintosh. Hostage is out now.

You do the same thing every day.

You know exactly where you're going.

You're not alone . . .

When Zoe Walker sees her photo in the classifieds section of a London newspaper, she is determined to find out why it's there. There's no explanation: just a grainy image, a website address and a phone number. She takes it home to her family, who are convinced it's just someone who looks like Zoe. But the next day the advert shows a photo of a different woman, and another the day after that.

Is it a mistake? A coincidence? Or is someone keeping track of every move they make...