After spending years in the Peruvian jungle during his tour in Army Special Forces, Cascade PD Detective James Ellison developed hyperactive senses, which came back to him five years after his return to the US. He can see people in darkened windows at night from two hundred yards, hear the music playing on the radio of the car he's chasing after he's lost sight of it, and can distinguish between wood and plastic after both have been in a three thousand degree fire. Blair Sandburg, a local anthropology student, tells Ellison that he is a "Sentinel," who in ancient ...
Jim tries to find a way for Sandburg to help him on duty. They need to talk to the Captain, but a terrorist manages to take control of Police Headquaters. Sandburg is one of the hostages. Ellison and Captain Banks try to figure a way to free all the hostages and take out the terrorists.
When undercover police officer Danny Choi is killed at the hands of Tommy Juno, Jim must use his senses and his skills as a detective to prove Juno's guilt. However, Juno seems capable of being two places at once.
The drug lab next door to Sandburg's apartment blows up leaving Blair homeless and getting Ellison involved in a local drug war. Blair moves in with Jim. Ellison teams with a former gang banger cop to try and stop an escalating drug war.
Blair woes the daughter of a suspected arms dealer in order to help Jim bring down the father and stop the escalating violence caused by the influx of powerful weapons. Jim has to deal with a female ATF agent with an abrasive personality.
Ellison's investigation of a series of diamond robberies is disrupted when Jim meets an attractive woman and is powerfully affected by pheromones. Sandburg connects this to Jim's odd reaction to evidence at the crime scenes.
Simon Banks and his son Daryl disappear from an anti-drug conference in Peru. Blair insists on going with Jim to rescue the Captain and his son, even if it means he has to jump out of an airplane and face drug runners.
When the car of Ellison's partner, who went missing a few years ago while he and Ellison were working on the kidnapping of the son of a wealthy, is found. But everyone seems heel bent on proving that he ran off with the money. Ellison believes that is not true. But an investigation reveals that Ellison could have been his accomplice and Ellison can't prove it. So he tries to find who the kidnapper is.
Cascade Police tries to stop a gang war between the Yakuza and a local biker gang by hosting a summit meeting. The leader of the bikers is poisoned and the Yakuza's female lawyer is suspected. Ellison discovers she's an undercover office.
A prostitute witnesses the murder of her pimp at the hands of a hired hitman known as the Iceman. Ellison and Sandburg have to provide protection for the woman while trying to figure out which of her clients is the hitman's target.
Ellison and Major Crimes work with a replacement bomb expert investigating a series of bombings targeting black churches. Sandburg tries to help Joel Taggart, Cascade's bomb expert, who has developed a phobia about explosives.