In a world ravaged by mutation, a teenage girl must travel into the forbidden Savage Zone to recover lost artifacts or her father’s life is forfeit. America has been ravaged by a war that has left the eastern half of the country riddled with mutation. Many of the people there exhibit varying degrees of animal traits. Even the plantlife has gone feral. Crossing from west to east is supposed to be forbidden, but sometimes it’s necessary. Some enter the Savage Zone to provide humanitarian relief. Sixteen-year-old Lane’s father goes there to retrieve lost artifacts—he is a Fetch. It’s a dangerous life, but rewarding—until he’s caught. Desperate to save her father, Lane agrees to complete his latest job. That means leaving behind her life of comfort and risking life and limb—and her very DNA—in the Savage Zone. But she’s not alone. In order to complete her objective, Lane strikes a deal with handsome, roguish Rafe. In exchange for his help as a guide, Lane is supposed to sneak him back west. But though Rafe doesn’t exhibit any signs of “manimal” mutation, he’s hardly civilized . . . and he may not be trustworthy.

Lane barely survived her first journey to the Feral Zone. The forbidden, overgrown landscape east of the Mississippi River was abandoned years ago when a virus spread through the population, bringing civilization to its knees. But Lane has crossed the quarantine line, and she knows the truth. There are survivors on the other side of the wall - people who were not killed by the virus, but changed by it, their bodies warped to display a variety of animal traits. In the most severe cases, their minds are warped as well, leaving them barely human. Lane volunteers to return to the Zone as part of a humanitarian aid mission. But she has a darker, secret purpose. Someone she loves has been infected, and she once made him a promise: If he ever goes feral, Lane will be the one to put him down. Now, Lane fears that the time has come.