Rome, 1965: Aspiring actress Silvia Whitford arrives at Rome’s famed Cinecittà Studios from Los Angeles, ready for her big break and a taste of la dolce vita. Instead, she learns that the movie in which she was cast has been canceled. Desperate for money, Silvia has only one choice: seek out the Italian aunt she has never met.

Gabriella Conti lives in a crumbling castello on the edge of a volcanic lake. Silvia’s mother refuses to explain the rift that drove the sisters apart, but Silvia is fascinated by Gabriella, a once-famous actress who still radiates charisma. And the eerie castle inspires Silvia’s second chance when it becomes the location for a new horror movie, aptly named The Revenge of the Lake Witch—and she lands a starring role.

Silvia immerses herself in the part of an ingenue tormented by the ghost of her beautiful, seductive ancestor. But when Gabriella abruptly vanishes, the movie’s make-believe terrors seep into reality. No one else on set seems to share Silvia’s suspicions. Yet as she delves into Gabriella’s disappearance, she triggers a chain of events that illuminate dark secrets in the past—and a growing menace in the present…