After one of its test rockets spirals out of control and explodes in a small community near a military base, Cyclone Rocket Company must relocate its plant to a safer, remote desert location. Having heard about the plant’s move from his former employer, maverick trucker Mitch Barton suggests to Cyclone’s head, Mr. Nelson, that he deliver the critical cargo and guarantees he can meet any deadline. Although wary of Mitch’s reputation, Nelson introduces the trucker to fuel developer George Lawrence, who explains that the plant cannot find a transport company willing to move three trucks, filled with nitric acid, hydrogen peroxide and hydrazine, volatile chemicals that make up the rocket fuel mixture. Because the new plant is situated far from any community, there are long stretches of unpaved roads over mountains, making the transport exceedingly dangerous. Nelson adds that in order for Cyclone to maintain its government contract, the plant must be operating in three days. To accomplish the job, Mitch demands Nelson supply him trucks, his choice of five plant men and five thousand dollars pay for each. Nelson agrees, notwithstanding his reservations about Cyclone’s spiritless workers. Mitch selects retired Marine sergeant Frank Miller, amiable drunk Pat Farley, obsessed gambler Ben and expert mechanic Joe but is displeased when Nelson informs him that George will be the sixth man. On the day of departure, a drunken Pat is driven to the plant by his younger brother Ken, but Mitch refuses to allow Pat to drive. Race car driver Ken volunteers to take his brother’s place and, despite his misgivings, Mitch agrees. As the journey begins, each man is motivated by how he intends to use the money. Frank, disillusioned by his inconsequential career after retiring from the Marines, has finally resigned himself to the fact that he will never be recalled to service and hopes the money will provide him and his unhappy wife Edith a new future, Ben hopes to win a fortune in Las Vegas and Joe confides in Mitch that he wants to go to college to earn an engineering degree. Saddened by Pat’s continual drunkenness, Ken plans to use the money to help cure his brother. Unknown to the others, George remains torn by the knowledge that the wild rocket may have failed because of the fuel mixture he developed and blames himself for the death of his wife and children, who were among those killed when the rocket struck the town. The men, two to a truck, proceed along the highway until turning off onto a mountain dirt road. As they proceed, Mitch spots a large boulder and realizes a rockslide has blocked most of the road. From outside the truck, Joe guides Mitch by the large rock and kicks away another falling boulder before it can strike the truck. George then safely guides Frank around the boulder, but Ken bets Ben that he can race through the gap safely without guidance. Afterward, Mitch chastises the younger man for his recklessness. The convoy proceeds carefully along the dirt mountain road several more miles until Frank requests a halt to examine the brakes on his truck. Mitch asks Joe to work on the problem and follow him and the other truck as soon as possible. While Joe makes repairs, Frank examines the tank containing the acid and notices that a cap has jiggled loose and is leaking the dangerous chemical. Recalling Edith’s constant disappointment in him, Frank abruptly seizes the acid-covered cap with his bare hand and tightens it. Later, Joe races with the semi-conscious, badly burned Frank to catch up with Mitch and the others. Examining Frank’s burned hand, George declares the acid has poisoned him and he needs immediate medical attention. Mitch guides the convoy back to a main road, only to run into a roadblock set up by the sheriff of a nearby town who want no part of the chemical-laden trucks. The sheriff agrees to take Frank to the hospital and the men are surprised by the arrival of Edith, who, having learned of Frank’s dangerous job that morning, has followed him. Shocked by Frank’s condition, Edith contritely pleads with her husband to forgive her continual nagging, but Frank dies in her arms moments later. The convoy is delayed as Mitch accompanies Edith and the sheriff to town to make a report on the accident. Upon Mitch’s return, the men continue in subdued spirits. After returning to the winding dirt roads, Ken is startled to hear honking further up the mountain and spots a school bus careening, brakeless, down the mountain. With no way to turn around on the narrow road, Ken manages to drive the truck safely into a ditch as the bus speeds by. Mitch and Joe stop their trucks and dive into the ditch, but in leaping away to avoid the speeding bus, Joe breaks his collarbone. The bus finally runs safely aground up an embankment and Mitch and the others repair it before resuming their journey. Hours later, Ken calls a halt to report continual engine problems. Joe diagnoses a broken oil line and Mitch, who has grown concerned by the approaching deadline, decides to drive the broken truck down the mountain pass road himself. As Mitch nears the end of the pass, the truck’s brakes give out and the men watch with alarm as Mitch struggles to control the truck over the last few curves before halting safely on a straightaway. Mitch then has the broken-down truck chained to both of the other trucks, one in front to pull it along and the other behind to slow it down. When Ben injures his hand while attaching the chain, Mitch asks George to steer the damaged truck. George confesses that he does not know how to drive a truck, but Mitch tells him that he cannot avoid his responsibility to the cargo despite his guilt over the failed rocket. The men make the final part of their journey in tension as they pull and prod the damaged truck along and finally safely arrive at the new plant. Surprised by the men’s new-found dignity at the success of their job, Nelson pays them and congratulates Mitch. Mitch arranges for Edith to receive Frank’s allotment, then, rethinking his cavalier attitude toward life decides to try something new.