When she inherits her eccentric grandfather's Essex Witch Museum, Rosie Strange is determined to sell up and cash in. On her first visit there she encounters Bronson, the enigmatic caretaker of the museum, and Sam Stone, an enthusiastic PHD student, who was helping her grandfather to drag the museum, with its wonky exhibits and moth-eaten tableaus, into the 21st Century. But before she can drop her bombshell on the museum's loyal
retainers, they are approached by an academic, George Chin, who wants them to find the remains of an executed witch from the 1500s – Ursula Cadence.

Despite her cynicism, Rosie finds herself sucked into the chase and, using her investigative skills - honed through her soul-rotting job as a Benefit Fraud Investigator – begins to unearth the extraordinary story of Ursula's tragic demise and her peculiar post-mortem journey. But someone else is after the remains, too. Who is the man in the dark Mercedes and what is his connection with a vulnerable child who appears to be the target of a demonic possession?

Rosie doesn't believe in the supernatural, but there's a strange magic descending over the Essex Witch Museum and if she doesn't keep her wits about her, it could be about to claim her too...