After a cheesy ghost tour in one of California’s oldest towns stumbles upon an actual haunting, a skeptical historian of the occult becomes entangled in solving a murder case.

When Professor Harper Grae loses a bet with a friend, she finds herself on a local nighttime tour of “haunted” locations in Monterey. Harper’s a lifelong non-believer in the occult, though her academic career is devoted to the historical and societal significance of witchcraft, ghosts, and medicinal poisons of all sorts. But her skepticism immediately gets tested when the tour stumbles on the body of local artist Delilah Mason—who’s found murdered on the grounds of a nearly two-hundred-year-old mansion, once home to the infamous Perles family.

On the night Mason’s body is found, Harper catches sight of something in the house that she can’t shake, something that’s impossible to explain, at least not rationally. Soon the murder investigation reveals that this is the second time a woman has been found murdered beneath a sprawling cypress tree in the gardens of the Perles Mansion. And when Harper’s closest friend is questioned by the police, Harper fears the authorities will fail to uncover the real killer.

As Harper asks questions around town and digs deeper into the supernatural speculation and rumors surrounding the murders—two women killed in similar circumstances, separated by nearly two centuries —she sees evidence she can’t ignore that the notorious mansion truly is haunted by the ghost of Isabel Perles.

What will it cost Harper to rethink everything she’s always believed to admit that the veil between the living and the dead might actually be crossed?