Lieutenant Braden discovers that Sally, the woman he's been falling in love with, has actually been checking out his qualifications to be a U.S. Navy frogman. He must put his personal life behind him after being assigned to be smuggled into a Japanese-held island via submarine to photograph radio codes.

Among the travelers of varied backgrounds that meet and interact on one night at Union Depot, a metropolitan train station, are Chick and his friend Scrap Iron, both newly released from prison after serving time for vagrancy. Hungry and desperate for a break, Chick fortuitously comes across across a valise abandoned by a drunken traveler. In it he finds a shaving kit and a suit of clothes with a bankroll, which help transform the affable tramp into a dashing gent. After buying himself a meal, Chick seeks some female companionship among the many hustlers who walk the station. He propositions Ruth Collins, a stranded, out-of-work showgirl and takes her to the station's hotel.

Two wagon caravans converge at what is now Kansas City, and combine for the westward push to Oregon. On their quest the pilgrims will experience desert heat, mountain snow, hunger, and Indian attack. To complicate matters further, a love triangle develops, as pretty Molly must chose between Sam, a brute, and Will, the dashing captain of the other caravan. Can Will overcome the skeleton in his closet and win Molly's heart?