Prior to the concert in the previous movie, Malcom receives a phone call from the FBI San Francisco office. Initially, the office congratulates them in saving the city, but they reveal that their resources were nearly wiped out, and have decided to end their alliance with the Arch Foundation to save up money to regain what was lost. Understanding the problem, Malcom hangs up with the FBI one last time, and relays the bad news to the others. Soon after the concert, Team Arch decides to leave San Francisco to relocate. After two months, they finally settle in the California capital of Sacramento.
Picking up where the previous movie left off, a surprised Riko wonders why her friend from Numazu, Hanamaru Kunikida, is in the Arch Foundation's headquarters. Hanamaru explains that she has heard about a 4th Of July Race, and has volunteered to give out flyers. Riko decides to introduce Hanamaru to the rest of Team Arch, while showing the advertisement of the race. Interested, Kaz and the JET decide to enter to help keep the business up and running.
While practicing, the JET discovers that Nolan Radcliffe and the House of Radcliffe are also competing, having been pardoned after their actions (See https://www.deviantart.com/kid-z4p/art/Team-Arch-11-Saving-Home-837477704). During practice, a bank robbery occurs, which leads to the JET and the House teaming up to stop the crooks, much to everyone's surprise, and Nolan's chagrin.
The next day, the JET barely qualifies for the race, but a group of delinquents ambush Nolan, who deliberately frames Kaz for it. Eventually, Hanamaru provides evidence to prove Kaz's innocence, but by the time Kaz is released, the same group of delinquents hijack Kaz's racing buggy. SpongeBob, Riko, and Tai manage to find the buggy, except for its engine. Tai stumbles across a dangerous-looking green item near the buggy and secretly grabs it while SpongeBob and Riko aren't noticing, before dumping it in a nearby swamp.
With all the auto mechanic garages filled with customers, the team decides to make their own engine, with Myron and Sanya obtaining some missing pieces. By the time Kaz's buggy is fixed, Nolan rigs the race to start without the JET, but despite that, the JET manages to win the race.
Before the team could even celebrate, one of the guards at the Radcliffe Family's new California consulate calls in with some bad news: A band of mercenaries have invaded the consulate, robbing the contents of one of the safes, and kidnapping Nolan's estranged disabled younger sister, Lana. One of their cars is a 1957 Chevrolet with a white spade on the hood and black fire details on the sides. Nolan immediately recognizes the car as it belongs to an old friend of the Radcliffe Family:
A month after Greymon's first appearance, a young Nolan; his father, Reagan; his uncle, Vince; and family friend Chip Mallow go on a smuggling run to smuggle a stash of uranium into Japan, but the plan is thwarted after Chip is captured. Chip asked the family to lie for him, but Nolan declined, claiming that he'd rather do it for his newborn sister. Meanwhile, Reagan and Vince agreed to lie for him, but ended up breaking the promise after almost getting into trouble, which resulted in them turning in state's evidence, leading to Chip being sentenced to 30 years in prison. Eventually, an appeal was made, and his sentence was reduced to a 3-month house arrest, but he ended up disappearing afterwards. Rumor went out saying that he died in a swamp after his cowboy hat was found, but his body was nowhere to be seen.
Tai, the Digital Heroes, and the rest of Team Arch decide to help rescue Lana. They originally decide to use the race reward money to pay a ransom demand, only to learn that the reward money was among the contents that were robbed from the consulate. For Plan B, they split up to search all over the state to find Chip's hideout. They find it at an old barn near a ridge, where they are ambushed by some of Chip's cronies. After disposing them, the team encounters Chip himself, who has Lana tied up. Nolan makes a deal: If Chip wins, he can keep the money, and providing that he release Lana, he can have the Radcliffe estate. If he loses, he has to release Lana, give the reward money to the JET, and turn himself in. Kaz goes one-on-one with Chip and wins the race. Chip releases Lana, but makes a run for it with the money. Fortunately, Kaz and SpongeBob manage to catch him before he could reach the county line.
With the money in hand, Team Arch manages to stay in business, and the House goes straight after bringing Chip to the authorities. As the team continues to find a new partner, Tai gets a phone call from Joe, who frantically tells him about an incident involving Mimi, prompting Tai to rush out of the building.
