In 1755, Abel Cloudesley, a London watchmaker and creator of remarkable mechanical automata, is mourning his wife, Alice, who died giving birth to their son, Zachary. Six years later, Abel is further devastated when a freak workshop accident takes Zachary's eye. With his new eye made of gold and lapis by Abel's soft-spoken apprentice Tom, Zachary, now with an astonishing gift of second sight, is sent to live with his eccentric Aunt Franny in the country. Abel buries himself in work until he is coerced by shadowy figures into designing a chess-playing automaton and delivering it to Constantinople to spy on the Sultan of the Ottoman Empire. After meeting the Sultan, Abel is not heard from again. Years later, teenage Zachary receives a letter suggesting that his father is still alive, a prisoner of the Sultan. Zachary sets off on a perilous journey to the Levant, determined to find Abel and bring him safely home.