Paris, 1889. The city is vibrating with the excitement of the Exposition Universelle and the imminent unveiling of the magnificent Eiffel Tower. Lucian Vance, a disgraced former military engineer turned reclusive clockmaker, wants nothing to do with the celebrations. But when his former mentor is found murdered in Lucian’s shop—clutching a bloody, intricately designed mechanical puzzle box—Lucian is framed for the crime. Forced into the treacherous Parisian underground, Lucian teams up with Amelie Laurent, a fearless investigative journalist. Together, they unlock the box to discover a terrifying Prussian conspiracy: a devastating clockwork bomb designed to level the Eiffel Tower during the opening ceremony, assassinating the French President and plunging Europe back into war. With the police hunting them and a ruthless cell of foreign agents closing in, they have less than forty-eight hours to climb the Iron Lady and stop the final tick.