The conflict with Cornelius Marx is over. Determined to move forward, Adelynn Spencer eagerly charges into her new marriage to Detective Inspector Baze Ford and steals away with him to the countryside city of Bath. While Adelynn wrestles to escape her recurring nightmares of the Irish magician—both waking and sleeping—Baze seeks the city’s legendary waters, hoping they’ll cure his damaged leg and break his growing opium addiction.

Just when they settle in, a string of poisonings strikes Bath—and Adelynn’s visions return. But this time, one of the victims survives, bringing her face-to-face with Katherine Quinn, a fiery woman with a penchant for magic and a mysterious bond to Ireland. Katherine soon reveals a shocking secret that causes Adelynn to question everything she once knew about her gift.

As Baze and Adelynn desperately try to focus on their marriage and the investigation at hand, Baze’s destructive dependence on opium and Adelynn’s obsession with uncovering Katherine’s shadowy past begin driving them apart. Can they reconcile and catch the killer before poisonous plans bring about deadly consequences?