When Avis Lovelock agreed to sail on Excambion, she didn't realise she agreed to a journey filled with ghosts... and a spiritualist who sees in Avis what no one else can. Strangely, nobody ever thanks Avis when she exposes mediums for the fakes they are. Avis Lovelock is a professional sceptic. Using her sharp insights and powers of observation, she sets out to debunk every nefarious spirit medium and psychic she can find. When she is invited aboard the ocean liner Excambion to take her skills to America, Avis discovers she has been hired to prove to potential buyers that the vessel is not haunted. As she begins her investigations, she runs afoul of the famous twin spiritualists onboard, Gideon and Rachel Duquesne. The more Avis works to discredit her adversaries and absolve the ship of its haunted reputation, the more she has visions of water filling her cabin, drowned bodies on decks, and flickering lights on the sea. Then someone is found dead. To discover the truth, Avis must join forces with her opponents, and confront some haunting secrets of her own.