The sole survivor of an Army plane crash in the Peruvian hinterlands, Jim Ellison subsisted for nearly two years on his raw animal instincts. When he returned to America and became a police lieutenant, Jim discovered that the abilities that had kept him alive in the jungle now gave him extraordinary senses of perception. With the help of Captain Simon Banks and a grad student Blair Sandburg, Jim now attempts to use these powers to apprehend a terrorist bomber called the Switchman.

The town of Cascade is brought to its knees when Garrett Kincaid, a notorious criminal that Jim Ellison had arrested years before, seizes control of the town's police station with the help of his gang of felons.

Jim and Blair are assigned to escort Derek Wilson, a key witness in a local homicide case, on his train ride from Oregon to the courthouse in Cascade. Wilson has essential information that will link his employer to charges of arson and murder.

Blair forces Jim to take a vacation at a remote monastery. Initially reluctant, Ellison begins to enjoy the solitude until one of the monks is found dead.

When Blair unknowingly moves into an apartment next to the drug lab of a local gang (dubbed the 357), Jim suddenly finds himself embroiled in the beginnings of an all-out gang war.

While guest-lecturing in Blair's anthropology class, Jim saves the entire building from a deadly gas leak only to discover that the leak was designed to distract the campus' attention while a canister of the Ebola virus was being stolen from the hazardous materials lab.

Jim's sentinel abilities detect something strange at the crime scenes of all the recent jewelry robberies but he's unable to figure out exactly what's causing the reaction.

After witnessing the death of undercover officer Danny Choi at the hands of a sniper named Tommy Juno, Jim uses his enhanced vision to identify and apprehend the killer. But the case against Juno is thrown out of court when its decided that no human could possibly have seen as far as Ellison had claimed.

Blair and Jim, along with forensics specialist Carolyn Plummer, suspect that a series of seemingly unrelated murders are actually the work of a serial killer.

After stopping an armored car heist, Ellison is struck by the high-tech weaponry at the criminals' disposal.