As a long undercover assignment ends, Special Agent Mark McCabe of the US Fish and Wildlife Service learns that the bullet-riddled, bloodstained SUV found in the Mount Shasta Wilderness belongs to biologist Jesse Hall, his ex-girlfriend. Jesse was studying the only known wolf pack in the area, and that pack was shot and killed the day she disappeared.

A wolf-hunting craze spread by a site on the dark web that offers high bounties adds more intrigue in the search to find Jesse. McCabe can't accept that she's likely dead. So, he consults with the FBI as a wilderness expert-but continues to investigate on his own, reaching out to poachers and hunting guides, a rifle-range owner, and the angry spouse and son of an eccentric mountain man who has gone missing.

Leads have dwindled and the search has stalled when a ransom demand arrives at the Sacramento FBI office. Mikayla Hebert, the FBI special agent in charge, joins the other local law enforcement to do a wider house-to-house search. . .but the answer lies in the wild.