Curator of paleontology Dr. Simon Nealy never expected to return to his Pennsylvania hometown, let alone the Hawthorne Museum of Natural History. He was just a boy when his six-year-old sister, Morgan, was abducted from the museum under his watch. After a recent breakup and the death of the aunt who raised him, Simon feels drawn back to the place where Morgan vanished. But from the moment he arrives, things aren’t what he expected. The Hawthorne is a crumbling ruin and plummeting toward financial catastrophe. Worse, Simon begins seeing and hearing things he can’t explain. Terrified he’s losing his grasp on reality, Simon turns to the handwritten research diaries of his predecessor and uncovers a blood-soaked mystery 150 million years in the making that could be the answer to everything.

Grayson Hale, the most infamous murderer in Scotland, is better known by a different name: the Devil’s Advocate. The 25-year-old American grad student rose to instant notoriety when he confessed to the slaughter of his classmate, Liam Stewart, claiming the Devil made him do it. When Hale is found hanged in his prison cell, officers uncover a handwritten manuscript that promises to answer the question that’s haunted the nation for years: Was Hale a lunatic, or had he been telling the truth all along?