Paris 1888. Armand and Odilon are young apprentice draughtsmen in the offices of Gustave Eiffel, working on what will be the engineer's greatest invention and the city's most famous landmark. The Eiffel Tower is the symbol of a new age, but in the exotic gas-lit streets of Paris, strange beliefs, dark desires and mysterious forces are loose. Soon Armand and Odilon find themselves involved with a spiritualist society who hold seances in the Paris Morgue, a card-reading clairvoyant, a female ventriloquist with a shady secret and a spirited young actress. Behind them all are the scheming machinations of Gordon Hole, an ambitious American architect who has vowed to destroy the Eiffel Tower before it can even be completed.