Mike watches football as KITT zooms through the Arizona desert. KITT urges Mike to review the cover ID for his next assignment; Mike reminds KITT that he doesn't have to do everything he's told. Sarah dials in to run a new algorithm on KITT's transformation system. When she admits to having no plans for her birthday this weekend, Mike promises to take her out after completing his mission.
Billy shows up at work all beat up. When Zoe asks what happened, he pretends that he had a basketball accident. She presses for the real answer, so Billy admits that he got into a fight with a fellow geek gamer over Warcraft cracks. Zoe advises Billy that it's time he learned how to fight, and offers to give him lessons after work.
Mike will go undercover as AWOL Special Forces operative Jack Miller to infiltrate the compound of Walt Cooperton, who is training a private, right-wing militia. Six months ago, the Department of Defense terminated Cooperton's contract, but they won't say why. Two weeks ago, Cooperton purchased state-of-the-art triggering devices for multi-megaton ballistic weaponry. Mike is to find the weapons and disarm them, all without wearing his earwig, which could compromise his cover.
Mike has KITT transform to 4X4 mode as he pulls into a general store in Arizona. KITT identifies Lieutenant Oren Moss and several other armed men in the store, warning Michael to steer clear. But Mike picks a fight to introduce himself as Miller and announce that he's looking for Cooperton. When Moss and the guys take off in their Hummer, Mike hops in KITT, delighted at the prospect of a backcountry chase.
Mike finds himself tied to a chair in a windowless tent, where drawling Southern paramilitary Cassandra interrogates him violently, demanding to know why he's there. Despite several minutes on the other end of a fire hose, Mike maintains his sense of humor, and finally wins a meeting with Cooperton.
In his office tent, Cooperton fills Mike with anti-government rhetoric. His organization is dedicated to taking down the government, a right given them by the Declaration of Independence. Mike claims he is of like mind. After reviewing Mike's fake military records, Cooperton sends him to get cleaned up for dinner.
In the latrine, Mike cuts an earwig out of his leg and makes contact with KITT, to plan the evening's surveillance. Cassandra is waiting for Mike when he exits the latrine - why is he talking to himself? Cassandra tries to fight Mike, but he quickly overwhelms her, concluding that she "likes it rough."
As Zoe instructs Billy on the finer points of fighting back at the SSC, KITT helps Mike sneak through Cooperton's compound to the office tent. Mike whips out a flash drive to access Cooperton's laptop, and then takes a look around. Strangely, Cooperton's possessions include a luxurious watch, Armani suits, and fine French wine - hardly the stuff of a right-wing extremist. Something's not right. Mike orders KITT to do a deep background search on Cooperton and everyone in his organization.
KITT locates a truck with traces of explosives at the far end of the compound, but there's nothing in it but a pile of pallets. KITT warns Mike that someone's on his tail. It's Cassandra, and in a flash, she and Mike are both pointing their pistols at each other. Cassandra reveals that she's really British MI6, undercover for over a year. Cooperton has acquired a massive MOAB bomb, and must be planning to knock something down.
As proof that she's not setting Mike up, Cassandra lowers her pistol, just as KITT senses several armed men approaching. He meets Mike and Cassandra and they jump in, only to be chased by several Humvees. Amazed, Cassandra sobers up when KITT announces that the road is full of mines and begins evasive maneuvers. KITT is thrown into the air while transforming by one of the explosions. Upon landing, he can't function, so he tells Mike and Cassandra to run for it or face certain death.
KITT reports that his undercarriage has been damaged; he will have to shut down and reboot to repair himself. Both Sarah and KITT advise Mike to run south. Cassandra almost falls off a cliff overlooking the river, only to discover that the only way to escape is to jump, despite the high risk of injury.
Cassandra hurts her ankle in the jump, and Mike's earwig stops working. Cassandra wants Mike to leave her behind, but he refuses, suggesting that they both take off their clothes and find shelter, as they're approaching stage two hypothermia. Sarah insists that KITT divert power from fixing himself to get a visual on Mike, just as he starts making out with Cassandra - a strategy to raise their core temperature.
By sun up, the paramilitaries have disappeared, and Mike knows something's wrong. KITT picks up Mike and Cassandra at the evacuation point, and Torres informs them that Cooperton and his men are hitting the road with the bomb. Since KITT's not quite Mike drives and Cassandra plots a course to intercept the trucks.
KITT is finally able to begin the background searches on Cooperton and his men, only to discover that Cooperton and Moss are European mercenaries implicated in a major bank robbery in Dubai. They escaped, but their affiliation with the Department of Defense was ended. The truck containing the bomb splits off from the pack of Humvees and heads for the Franklin D. Roosevelt Memorial Dam.
Torres alerts the Phoenix police, while Mike climbs out the window onto KITT's hood so he can jump into the remotely driven truck. As the bomb's clock counts down the final ten seconds, Billy and Sarah argue over which wire Mike should cut to disarm the bomb. Luckily, he cuts the right wire in the nick of time, and KITT is able to stop the truck, just as the entire Phoenix Police Department shows up.
Sarah learns that a massive gold shipment of $250 million is being moved to the Federal Reserve in Phoenix - the bomb was just a decoy. The biggest gold heist in U.S. history gets underway as KITT screeches to the scene, resulting in a stand-off. Cooperton tells Mike to stand down, but he laughs, watching KITT transform into Attack Mode, then orders him to deploy missiles.
KITT incinerates a Humvee just as the Phoenix cops pull up to arrest Cooperton and his men. Mike and Cassandra share a heartfelt good-bye kiss, which is captured on camera by KITT for the benefit of everyone back at the SSC, including Sarah.
During another training session, Billy impresses Zoe with his moves so much that she invites him to buy her a drink... someday. Sarah prepares to spend her birthday in her pod, claiming she's just not into it. KITT wishes Sarah happy birthday, then shows her video of Mike and Cassandra from last night. Mike declines Cassandra's invitation to make love, claiming there's someone else and it's complicated.
Mike appears on a chatline in Sarah's pod, asking her to come to the SSC. Dressed for a date, Mike surprises Sarah with a bottle of Chateau Margaux, and asks her if she'd like a ride in his car. Sarah admonishes KITT that he's not supposed to joyride, but he reminds her that he doesn't always have to do what he's told.