Robert Stonewall Jackson was nicknamed "Stony" by a fellow Vietnam Marine for how emotionless he killed so many. Overcoming addiction and PTSD via fly fishing, he's a fishing guide Near Fort Collins, Colorado, helping others to overcome their own monsters.

Stony investigates fish kills on the Cache La Poudre River. Then an Asian friend of his Vietnamese American, "adopted" daughter is killed in her tent near the source of the Poudre, Stony's stomping grounds. Suspicion is a bear attack, but after seeing the postmortem, Stony thinks differently. And then someone shoots at him in the middle of town.

Crime scene clues of the Asian woman lead Stony's friend, Detective O.J. Cromwell, and a National Parks Special Investigator, Suyin Yeong, to two stoner brothers. But while on a fishing trip in Pensacola, Florida, Stony's good friend, Dr. Jake Roberts, is nearly killed by a speargun arrow from a mysterious diver. And while Jake is in ICU, Stony's "adopted" daughter, Kim Lyn, is murdered outside her restaurant.

As the body count rises, Cromwell and Yeong realize clues about the stoners were planted. Murder of two Asian women reeks of blooming prejudice surrounding the new President. Their search focuses on a white conservative ranching town in North Park, Colorado.

High levels of uranium are found in the killed fish. A man camping near the Poudre source, turns up in ICU with a severe and unusual pneumonia. All of it seems to have a connection to the water supply and the Grand Ditch diversion canal. Cromwell wonders if this is connected to the murders.

Cromwell increases security at Kim Lyn's special Vietnamese funeral ceremony. But a shot rings out, and another of Stony's friends falls. Stony believes someone has a grudge, killing his friends and family to make him suffer. The last shot points to a specially trained sniper, possibly from Vietnam. Stony leads the killer away from his wife to his high-country stomping grounds. But the wilderness is also the killer's home.