When a guest turns up dead at the newly opened Pinnacles Grand Hotel, ISB agent Felicity Harland finds herself summoned to a peculiar scene. A gentle breeze blows in from the balcony window, belying the violence of a man stabbed to death in his hotel room. It’s clear to Harland that this murder was personal, especially when the victim’s wife admits that she wanted him dead.

But Harland isn’t so sure that this was a domestic dispute gone bad. When she hears about the Park Service searching for a missing person out on the trails, she sets out with her partner, Ferdinand “Hux” Huxley, to see if the two cases are connected.

As Harland and Hux take on the rocky, exposed terrain of California’s ancient volcanic wonderland, they soon realize that the mystery at the Pinnacles Grand is not at all what it seems—and that a predator may be closing in.