In 1889 Paris, treasure hunter and wealthy hotelier Séverin Montagnet-Alarie is given the opportunity to hunt a rare treasure for the Order of Babel, an organization of two powerful houses who are in charge of protecting the West's Babel Fragment. Séverin, the rejected heir to one of the houses, longs to claim his inheritance, but is often thwarted by his childhood rival Hypnos. Hypnos employs Séverin to retrieve the Horus Eye, which can reveal the location of a Babel fragment, so Séverin assembles his eclectic team--and what they find could change the course of history.