Tobey Marshall is a former professional race car driver who now runs his late father's garage, Marshall Performance Motors, in Mount Kisco, New York. Here, he works alongside his friends to tune up performance cars while trying to stay afloat financially. To supplement their income, they take part in underground street races when the sun goes down. Amidst this struggle, Tobey's friend Pete envisions the possibility of him competing in the De Leon, which is regarded as a premier, high-stakes supercar street race organized by the enigmatic radio host known as Monarch.
The plot takes a turn when Tobey’s old adversary, Dino Brewster, pressures him and his crew to finish restoring a vintage Ford Shelby Mustang — a project initiated by the late Carroll Shelby. In exchange, Dino promises them a 25% cut of the profits from the sale of the car. After its completion, the Mustang is showcased at an auction party in New York City, where Tobey encounters Julia Maddon, an English car broker. Julia's client, Bill Ingram, shows interest in purchasing the car, provided that they can demonstrate it can hit speeds above 230 mph, a claim that Tobey confidently makes. Ignoring Dino’s reservations, Tobey takes the Mustang to a nearby race track and successfully proves its capability by reaching 234 mph, leading to Ingram agreeing to buy the car for a staggering $2.7 million.
However, tensions escalate as Dino, feeling overshadowed, challenges Tobey and Pete to a race. The stakes are high: if Tobey wins, he walks away with Dino's entire share from the Mustang sale, but if he loses, he must forfeit his own. The race, conducted with Dino's uncle’s three illegally imported Koenigsegg Agera R vehicles, takes a devastating turn when Dino, in a desperate attempt to win, deliberately crashes into Pete’s car, sending it tumbling down a ravine, resulting in Pete’s tragic death. With Dino disappearing from the scene, Tobey finds himself arrested and ultimately sentenced to two years in prison for involuntary manslaughter, unable to vindicate himself by proving Dino's involvement in the crash.
Upon gaining parole, Tobey is resolute in seeking vengeance for Pete's death. He decides to enter the De Leon utilizing Ingram's Mustang, but he must adhere to the condition that Julia accompanies him during the drive. With just 45 hours to reach San Francisco before the race begins, the duo embarks on a perilous journey. Along the way, they find themselves in a high-speed chase with the Michigan State Police, eventually uploading the footage, which garners attention. In a twisted move, Dino offers his exceptionally rare Lamborghini Sesto Elemento to anyone who can impede Tobey from participating, which puts them in the crosshairs of aggressive truckers.
As their journey unfolds, Tobey and Julia face an ambush by the truckers in Utah, but they receive unexpected aid from Benny, a member of Tobey's crew, who swoops in using a military helicopter he pilfered. Although he gets arrested for this stunt, Benny successfully delivers the Mustang to the Bonneville Salt Flats, allowing Tobey and Julia to reach San Francisco just in time to register for the race. Unfortunately, misfortune strikes again when a tow truck, operated by one of Dino's henchmen, collides with the Mustang, wrecking it and injuring Julia.
Desperate for a racing vehicle, Tobey approaches his ex-girlfriend Anita, who happens to be Pete's sister and now Dino's fiancée. Upon realizing Dino's involvement in Pete's demise, she shares the secret location of a hidden Koenigsegg, which Tobey and a crew member named Joe manage to retrieve. After reuniting with Julia at the hospital, Tobey confesses his feelings with a kiss, letting her in on his plan to drive for Pete.
On the following day, Tobey shocks Dino by arriving in the very Koenigsegg he raced when Pete was killed, presenting him with Anita's engagement ring as a declaration that she is no longer with him. During the adrenaline-fueled race along the Pacific Coast Highway, chaos ensues as racers and California Highway Patrol officers crash in succession, leaving only Tobey and Dino neck-and-neck. In a desperate maneuver to replicate the circumstances of Pete's death, Dino attempts to ram Tobey off the road. However, Tobey avoids the attack, sending Dino careening off the road.
In a decisive moment, Tobey rescues Dino from the wreckage and, overwhelmed by anger, delivers a punch as revenge for Pete. He then crosses the finish line in triumph, only for both men to be apprehended by the police, leading to Dino's conviction for Pete's murder.
Months later, 178 days after his release, Tobey is greeted by Julia at the prison gates while she drives a sleek 2015 Ford Mustang. Together, they set off toward a prison in Utah to pick up Benny, who is being released early for good behavior, marking the end of a tumultuous journey fueled by speed, loss, and redemption.