NAMED A BEST BOOK OF THE YEAR BY ESQUIRE 'This twisty, absorbing thriller is both a moving love story and fascinating speculative fiction exploring memory, time and reality' GUARDIAN 'An expertly crafted puzzle of a story' NEW SCIENTIST 'Old-school creepy... a five-star horror novel' STEPHEN KING on Ascension 'A vivid, unputdownable story, about love and loss and all it means to be human' SUNYI DEAN, Sunday Times bestselling author of The Book Eaters 'An outstanding puzzle box of a novel ... thrilling, intelligent sci-fi with a touch of horror' GARETH BROWN, internationally bestselling author of The Book of Doors In this staggeringly mind-bending speculative thriller for fans of Blake Crouch and Ted Chiang, a woman dives into her husband's memories to uncover a decades-old threat to reality itself... Maggie Webb has lived the last decade caring for her elderly husband, Stanley, as memory loss gradually erases all the beautiful moments they created together. It's the loneliest she's ever felt in her life. When a mysterious stranger named Hassan appears at her door, he reveals a shocking truth: Stanley isn't losing his memories. Someone is actively removing them to hide a long-buried secret from coming to light. If Maggie does what she's told, she can reverse it. She can get her husband back. Led by Hassan and his technological marvels, Maggie breaks into her husband's mind, probing the depths of his memories in an effort to save him. The deeper she dives, the more she unravels a mystery spanning continents and centuries, each layer more complex than the last. But Hassan cannot be trusted. Not just memories are disappearing, but pieces of reality itself. If Maggie cannot find out what Stanley did all those years ago, and what Hassan is after, she risks far more than her husband's life. The very course of human history hangs in the balance. 'A compelling narrative that takes the reader on a page-turning journey through both time and memory' T.R. Napper, award-winning author of 36 Streets 'A tender and compelling tale of love and memory across time and history. Thrilling, thought-provoking and melancholy. Superb' David Wragg, author of The Black Hawks