Youngest sister Grace Fairfield is the family rebel. Fun-loving, clever, and creative, she elevates rebelliousness to an art form, often resulting in chaos in Dark Hollow. When Grace is assigned her first Hex Support case at a haunted amusement park, she’s thrilled to revisit her beloved stomping grounds from college.

Unfortunately, the case involves an employee found dead on an expensive new rollercoaster that's supposed to bring in enough revenue to prevent the park’s closure. Grace needs to act fast: if she can solve the case by Halloween, there's still a chance the new rollercoaster can open in time to save the park from bankruptcy.

There is, however, one teensy complication in the form of Luke Brookstone, an old flame who worked at the park with her during college breaks. Even more distracting: he's human and knows nothing about the magical world. Despite their chemistry, Grace knows that a relationship with a human would be met with nothing but disapproval by her witchy ancestors. Then again, when was Grace Fairfield ever one to fall in line?

The clock is ticking on the fate of the amusement park, as well as Grace's reunion with Luke. Can she stop the killer in time to save her beloved park, or will it all go downhill from here?