"The author of the smash bestseller, I Let You Go, propels readers into a dark and claustrophobic thriller, in which a normal, everyday woman becomes trapped in the confines of her normal, everyday world ... Every morning and evening, Zoe Walker takes the same route to the train station, waits at a certain place on the platform, finds her favorite spot in the car, never suspecting that someone is watching her ... It all starts with a classified ad....