The Vanishing by Jayne Ann Krentz

Forty years ago in the small town of Fogg Lake, ‘The Incident’ occurred: an explosion released unknown gases, causing peculiar effects on its residents, including strange visions and ominous voices. Not wanting the government to get involved, they chalked it up to the hallucinogenic effects of mushrooms. Little did they know these effects would linger through the generations . . .

Residents Catalina Lark and Olivia Dayton have been best friends for years and own an investigation firm together, using what they call the ‘other sight’ to help with their business. When Olivia goes missing, Cat frantically begins the search for her. When scientist Slater Arganbright shows up, she accepts his help even though there’s something about him she just can’t trust.

The duo discovers someone is hunting the witnesses of a murder that happened fourteen years ago – the very one Cat and Olivia witnessed as teens. Cat and Slater’s search for Olivia takes them down a rabbit hole that is far more dangerous than they ever expected, and with a killer in their midst, neither of them can foresee who will come out alive.