On Vernon Praisworthy's first day as a short-order cook, he is immediately overwhelmed by the morning rush as soon as he is left alone on the line. When the grease catches fire, Vernon accidentally grabs the grease bucket and throws it on the flames. He is promptly fired for nearly burning down the diner. Vernon cheers himself by walking to a nearby sandlot where he works with a group of kids, telling them that whenever he gets enough money he will buy them uniforms and a real baseball diamond. A man named Kotch flashes his badge at Vernon and says he wants Vernon to meet someone. Though Vernon thinks Kotch is taking him to jail, the man drives him to an enormous estate. Inside, Vernon sees vintage electric trains in display cases and several layouts where toy trains run through miniature countrysides. A German shepard, Bo, greets Vernon, followed by R. R. "Choo-Choo" Trayne, the billionaire Chief Executive Officer of Trayne Exterprises and other corporations. Trayne was also once a hobo who rode on the railroads he now owns. Mitchell, Choo-Choo's right-hand man, informs Vernon that, as the son of Choo-Choo's long-lost sister, he is last of the line and will inherit the Trayne empire. While Choo-Choo is concerned about Vernon's spotty employment record of thirty-nine jobs in thirty-four cities, he appreciates the time that Vernon spends helping poor children. Choo-Choo tells his nephew, that since hoboing taught him everything he needed to know to become a billionaire, he wants Vernon to prove his ability to handle the Trayne empire by "riding the rails." He tells Vernon to stop using the name Vernon Praisworthy and think of himself as "Joe Smith." Vernon must get to Seattle, Washington, in six days, whereupon he will receive his next destination by mail addressed to general delivery at the post office. Mitchell lays out the rules Vernon must follow: He cannot disclose his relationship to Choo-Choo Trayne, nor contact Choo-Choo unless instructed, nor steal to survive, nor deviate from the route he is given. He must also travel with Bo, "the world's smartest dog," who will look after him. Later, as Vernon attempts to catch the next train to Seattle, he jumps on the wrong train. A yard man contacts Choo-Choo, who orders the train stopped and then chuckles over the mistake because he hopped a wrong train his first time, too. Hitchhiking back to town, Vernon accepts a ride from Steve and Ernie. Although Bo doesn't want to get into their van, Vernon overrides the dog's decision. At a phone booth, Steve calls Rita and Jen, who both work at the security desk at Trayne World Airways, to tell them that Dave, their regular getaway driver, was arrested in a bank robbery, but they have found a replacement. Steve and Ernie drive Vernon home and tell him that they have a job for him before he returns to the rail yards. The next morning, Rita and Jen are dressed in their airline uniforms, while Steve and Ernie are disguised as guards. The two drive Vernon to the airport, give him keys to the van, and tell him to park in a nearby lot. When Vernon walks back to the airport, he joins a crowd watching a Chinese woman, Madame Wong, disembark from an airplane with a dog. Television newswoman Barbara Henderson explains that the Republic of China is delivering a Shar-Pei canine named Li Chien Wu as a gift to the President of the United States -- and that the exotic dog has been insured for $100,000. Nearby, Steve and Ernie hijack the city pound’s “petmobile,” lock the guards in back, and arrive at the ceremonies. Madame Wong hands Li Chien Wu over to U.S. State Department representative Leonard Cox, who in turn gives the Shar-Pei to the imposter guards, Steve and Ernie. When Bo barks and tries to grab Li Chien Wu’s leash, Cox and Vernon pull them apart. Watching the ceremonies on television, Choo-Choo is surprised to see Vernon and Bo, wondering why they are not on a train to Seattle. After Vernon and Bo return to the van, Steve and Earl, carrying a pouch, also arrive and climb into the back. Vernon drives them all away. When Bo opens the pouch to reveal that Li Chien Wu is inside, Steve and Earl explain that they will drop off the dog after they take Vernon and Bo to the rail yard. However, Vernon realizes that Steve and Ernie were the airport guards. At gunpoint, they order Vernon back to the house, put him under guard, and lock Bo in a shed. Steve calls Cox with a $100,000 ransom demand, but afterward, when Cox unthinkingly tells Barbara on-air that he would have paid twice that amount, Steve calls back and increases the ransom to $200,000. Bo escapes the shed and sneaks into the house where he steals Steve’s pistol, gives it to Vernon, and leads Li Chien Wu out the door by the leash. As Vernon follows, he hits his head and knocks himself out. When Steve, Ernie, Rita and Jen leave to collect the ransom, Bo leads the Shar-Pei back into the house and enlists a door-to-door salesman to untie Vernon. As Vernon rushes to the drop-off point in the van, he runs out of gas and steals a car. Meanwhile, the kidnappers evade F.B.I. agents and give Cox instructions to leave the money in a bathroom stall. Cox makes the hand-off to Steve, who takes the briefcase into another stall, transfers the money to a box, and flushes the location responder hidden in the briefcase down the toilet, leading agents after it. Steve passes the box to Ernie, who delivers it to Jen and Rita. However, Vernon snatches the box and runs. Steve knocks Vernon out and takes the box back, but Bo snatches it from Steve. As Bo, Li Chien Wu and Vernon escape with the box in a car, the four crooks follow. Vernon crashes into a police car, and the police arrest everyone. Choo-Choo uses his contacts to slip into Steve and Ernie’s jail cell with a tape recorder to prove Vernon was set up and was not a fellow conspirator. When Vernon is released from custody, a police detective drives him back to the rail yards, where he and Bo resume their trip to Seattle.