Haven Ambrose, a trailblazing nautical archaeologist, has come to the sun-soaked village of Positano to investigate the mysterious shipwrecks along the Amalfi Coast. But she also is secretly on a quest to locate a trove of priceless gemstones her late father spotted on his final dive. Upon her arrival, strange maelstroms and misfortunes start plaguing the town. Is it nature or something more sinister at work? As Haven searches for her father’s sunken treasure, she begins to unearth a centuries-old tale of ancient sorcery and one woman’s quest to save her lover and her village by using the legendary art of stregheria, a magical ability to harness the ocean. Could this magic be behind Positano’s latest calamities? Haven must unravel the Amalfi Curse before the region is destroyed forever.

1873. At an abandoned château on the outskirts of Paris, a dark séance is about to take place, led by acclaimed spiritualist Vaudeline D’Allaire. Known worldwide for her talent in conjuring the spirits of murder victims to ascertain the identities of the people who killed them, she is highly sought after by widows and investigators alike. Lenna Wickes has come to Paris to find answers about her sister’s death, but to do so, she must embrace the unknown and overcome her own logic-driven bias against the occult. When Vaudeline is beckoned to England to solve a high-profile murder, Lenna accompanies her as an understudy. But soon they begin to suspect that they are not merely out to solve a crime, but perhaps entangled in one themselves.

Hidden in the depths of 18th-century London, a secret apothecary shop caters to an unusual kind of clientele. Women across the city whisper of a mysterious figure named Nella, who sells well-disguised poisons to use against the oppressive men in their lives. But the apothecary’s fate is jeopardized when her newest patron, a precocious 12-year-old, makes a fatal mistake, sparking a string of consequences that echo through the centuries. Meanwhile, in present-day London, aspiring historian Caroline Parcewell spends her 10th wedding anniversary alone, running from her own demons. When she stumbles upon a clue to the unsolved apothecary murders that haunted London 200 years ago, her life collides with the apothecary’s in a stunning twist of fate --- and not everyone will survive.