The airship Tristan is hijacked by a member of the Fleurs du Mal who demands the release of his comrades held in Vatican captivity. But one passenger stands in his way - Abel Nightroad.

The murder of clergy in Amsterdam, their bodies drained of blood, draws Lady Caterina's attention. The local vampires, fearing Vatican retribution, seek out those responsible as Father Hugue investigates.

Under house arrest, Lady Caterina finds herself face to face with a manipulative enemy. Abel's efforts to save her result in an encounter with a dangerous new foe.

Abel and Asta plan to plead Ion's case to the Imperial Council, and Ion and Esther search the city for answers. But when their trail leads to further intrigue, betrayal comes from beyond the grave.