Spanning London's occult seances to the Parisian catacombs, two women claim to have seen Marie Antoinette's ghost in the garden of Versailles in this Gothic supernatural mystery where magic and science collide.

1902. Helena Walton-Cisneros, known for finding answers to the impossible, has started her own detective agency. The agency's first uncanny cases are both located in Paris – itself too much of a coincidence to ignore.

First, two English women claim to have seen the ghost of Marie Antoinette in the gardens of Versailles. Then a young woman working at the mysterious Méliès Star Films studio has disappeared.

As Helena and her colleague Eliza investigate, they uncover vanishings, impossible illusions, demons in the Catacombs and connections to the occult. To find the thread that connects the cases, Helena and Eliza must accept the natural world is darker, stranger than they could ever have imagined…