Halley Ashwood is well on her way to achieving her dream of being a doctor. Focused and independent with a mother she never knew and a father who never loved her, the only constant Halley has ever had in her life is her brother, Flynn. Where Halley is logical and grounded, Flynn has always had an interest in conspiracy, but they’ve always been able to trust each other above anyone else. And Halley and Flynn don’t believe in making promises. That’s how Halley knows something is wrong when her brother leaves her a message the day before her scheduled trip to visit him in Amsterdam, asking her to promise him she won’t come.

When she arrives in Amsterdam, her brother is missing, leaving only his ominous words in his wake. Halley sets out to find out what happened to him and discover something she never expected. Turns out Flynn’s conspiracy theories maybe weren’t so farfetched after all. Demons are real, they’re living among us, and they may hold the answer as to what happened to Flynn.

Determined to find out the truth about her brother’s fate, Halley begins a dark journey that will force her to question everything she thinks she knows about the nature of the world, the forces within it, and even herself.