The Heights by Louise Candlish

A grieving mother becomes obsessed with the charismatic teenager she blames for her son’s death, and years after believing he was gone, she spots him alive on a London rooftop—reigniting a dangerous quest for revenge. As her fixation spirals, unreliable memories, secrets, and a true-crime-style retelling draw her deeper into moral gray areas, testing her relationships and sanity while exploring grief, guilt, and the unnerving pull of high places.

Purchase from Bookshop.org