In 1869, the United States begins a railroad mail service to the West Coast which proves highly tempting to train robbers, in particular an organized gang with one of the mail's supposed guardians in their pay. Prizefighter Steve Davis, a former army intelligence man, is hired to track down the gang and save the Territorial Mail Service. Steve goes undercover in territorial prison, leans Morse Code from a fellow prisoner, breaks jail, infiltrates the gang...and finds time to romance dance-hall singer Mary, who proves to have hidden depths...

An island pearl merchant and his new wife make room for a mysterious shipwrecked man.

Communists blackmail a shipping executive into spying for them.

After her father is murdered, a girl joins the police force in an effort to track down the killers.

During WWII, the publisher of the isolationist New York Gazette is murdered just as he was about to change the paper's policy and support the US war effort. His friend, a small town patriotic editor, is brought in to find the culprits.