In 1843, novelist Victor Hugo’s beloved nineteen-year-old daughter drowned. Ten years later, Hugo began participating in hundreds of séances to reestablish contact with her. In the process, he claimed to have communed with the likes of Plato, Galileo, Shakespeare, Dante, Jesus, and even the Devil himself. Hugo’s transcriptions of these conversations have all been published, or so it was believed. Recovering from her own losses, mythologist Jac L’Etoile arrives on the Isle of Jersey, where Hugo conducted the séances, in hopes of uncovering a secret about the island’s Celtic roots. But, Theo Gaspard, the man who has invited Jac there, is a troubled soul. He wants Jac to help him discover Hugo’s lost conversations with someone called the Shadow of the Sepulcher.