Billy moves a couch and easy chair into the KITT cave, in an effort to spruce up the joint. When Zoe tells Billy to move the chair for better feng shui, Billy takes offense; who died and left Zoe boss? Zoe claims Torres did. Anticipating a few days off, Mike decides he's going to get Zen with a visit to his favorite bar, Sonny's.
Sonny is a great guy and an amazing bartender, and it's been years since Mike has seen him, or his daughter Julie. Billy wants to tag along, but Sarah explains that they're all going to take some time off -- one at a time. When Billy asks when his turn starts, Sarah refers him to his new boss, Zoe. Billy is stunned, but everyone else thinks it's funny.
Mike is surprised to find the bar is a bit rougher than he remembered. A punk band performs on stage, and the mosh pit is barely controlled chaos. Bartender Robin asks Mike if he's come about the bouncer job; if he's a collection agent, he needs to get in line. Julie informs him that her dad Sonny died in a car accident three months ago. Now she's in charge, and times are tough. There's been three unexplained fires in the last two months and fights every night.
When Mike asks what he can do to help, Julie asks him to straighten out the mess at the door. Former bartender Eddie, a pacifist, isn't doing well in his new job as bouncer. Out in the parking lot, two bad guys approach KITT with larceny on their minds. KITT asks if he can administer non-lethal shocks, but Mike encourages him to stay Zen. The bad guys are amazed when their crow bar has no effect. KITT warns Mike that Terry Driscoll and his gang of thugs are armed and approaching the door.
When Terry's thugs bum rush Mike, he grabs Terry's nose and holds on, then grabs Terry's gun. Mike advises Eddie to take any fighters outside one at a time, and to call if he needs help. Mike calls Sarah to inform her of Sonny's death and ask for the SSC's help. KITT downloads all the files on the bar from the municipal database to the SSC. Zoe tells Billy to focus on the car accident, but he has trouble taking orders, preferring to research the unexplained fires. Soon enough they'll see who's right.
At the end of the night, Julie thanks Mike for his help. She's barely hanging on; maybe she's not cut out to fill her dad's shoes. Mike asks if anyone wants Julie out. When Robin pries, asking if Mike and Julie have history, Julie sends her back to work. Julie asks Mike if he'll stick around, and he agrees to attend the staff meeting the following morning at 11.
Billy hits a wall when he learns that the cops investigated Sonny's for arson, but came up empty. KITT wonders if Mike is idealizing Sonny's; Thomas Wolfe wrote a book about the phenomenon called, "You Can't Go Home Again." Mike and KITT are just leaving the club when they notice a fire around back. The door to the club is locked and Eddie is trapped in the middle of the fire.
KITT reports that the bar's spare CO2 tanks are dangerously overheated, so Mike orders him to drive through the fence and shoot CO2 at the fire to put it out. KITT opens his door for Eddie and offers an oxygen mask, while Mike asks him not to divulge what he's seen. Mike calls the fire in to Sarah, who's convinced it's arson. KITT can investigate the following morning while Mike is at the staff meeting.
Zoe learns that Sonny wrapped his 1968 Dodge Coronet around a telephone pole, no passengers or witnesses. She did find two neighborhood blog entries that mention only hearing the crash and nothing else. In the morning, Phil Driscoll crashes the staff meeting with his son Terry in tow. Terry's nose is broken and Phil wants an explanation before calling his lawyer. Mike explains that his policy is hands off until someone points a gun at him.
Phil smacks Terry in the back of the head and apologizes to Mike, who returns Terry's gun to Phil. Meanwhile, KITT scans the burn area with his spectrograph to isolate a chemical accelerant. Zoe and Billy race to upload a new sniffer program, as Mike visits Julie in her apartment over the bar. When she leans in for a hot kiss, KITT interrupts, claiming that he needs to follow the trail of the fire before it dissipates.
The bad guys that roughed up KITT spy him following the trail of the fire, and conclude that KITT is teasing them. They consider it a dare, and resolve to steal him later that night. KITT goes as far as he can, then sends Mike out of the car with a handheld spectrograph to follow the trail of what seems like methane. Mike stops at the door of Driscoll Development, Phil's company.
Mike gets Sarah on a chatline. It had to be Terry. Sarah's doubtful, thinking Terry is kind of a moron. Back at the club, Julie agrees with Sarah. Terry's dad Phil was Sonny's best friend and offered to buy the bar after his death. But that was more of a favor to Julie, since Phil only does big deals. Julie dated Terry once, but that was a long time ago.
Using a holographic projector, Zoe plays a hologram of a 1969 Dodge Coronet to recreate Sonny's accident. The bloggers said they heard nothing but the crash, thus no screeches or skid marks. Zoe concludes that someone cut Sonny's brake line, but Billy reminds her they need proof. Sarah resolves that they need to find Sonny's car.
Eddie confesses to Mike. He started last night's fire, thinking he could put it out and be a hero, but then he got locked out the back door. He apologizes, thanks Mike for saving his life, and asks who is Mike, really? Mike claims he's just a guy trying to make things better, then calls the SSC with the news that Eddie started the fire.
KITT locates Sonny's car in an art gallery presided over by wacky artist Eric, who's part of an artist subculture fascinated with car crashes, which disgusts Mike. Still, Mike puts on his game face to enter the gallery and investigate the car to confirm that its brake line was cut. Zoe was right -- Sonny was murdered. When Mike leaves the gallery, someone fires on him from a bridge overhead.
Even though KITT explains he'll exhaust his ammunition in seven seconds by laying down fire in a scatter pattern, Mike orders him to lay down cover fire so he can get in. Mike and KITT are followed by two SUVs as another two SUVs prepare to block the road under a bridge. Mike orders KITT to turbo boost them over the bridge and back to Sonny's bar.
KITT scans the crowd at the door to the bar -- there are even more concealed weapons than last night! The two bad guys approach KITT in the parking lot carrying a welding torch and portable gas tank. When they light the torch, a spontaneous explosion blows them into a wall, and they run off. When Zoe sees the video, she knows something's up. KITT wouldn't disregard Mike's order to stay Zen to cause the explosion.
Zoe and Billy simultaneously have the same idea, and rush to investigate the bar's real estate and geological records. It turns out that Phil paid for a confidential survey before Sonny's death. The bar is sitting on top of a pool of methane worth $50 million, explaining the explosion, the fires, and the constant fighting in the bar. Zoe and Billy call Mike with the news.
Mike tells Julie about the methane, but she still can't believe Phil is guilty, especially since he just died of a heart attack. Mike orders KITT to display files on Julie's monitor. Amazed, they find Terry's signature on the survey form. Meanwhile, Billy programs image recognition on Sonny's car, and Zoe hacks into all the businesses within a two-mile radius with camera surveillance. Sarah starts running footage from the day of Sonny's accident to find video of Terry cutting Sonny's brake line.
Terry enters Sonny's with his gang to start a good old-fashioned bar brawl with Mike. Robin throws Sonny's bat to Julie, who starts in on Terry's thugs, giving Mike the edge. After the fight, Mike falls off his bar stool, and Julie puts him to bed. She's hoping that Mike feels like sticking around. Mike quotes KITT, realizing he "can't go home again," but allows that he could stay for a few more hours.