Bill Fenwick, criminal lawyer, is becoming a mouthpiece for mobsters, when his brother George, a Justice Department investigator, is killed by mob chief Edward Selton. In atonement, Bill leaves his practice and his venal girlfriend and goes undercover in Nevada to investigate a scheme for "laundering" stolen gold bullion. He starts making progress when he pursues attractive Virginia, who's somehow involved with the gang; in fact, unknown to Bill, she's Selton's sister.

Terry is the chief car tester for Emery Motors and Frank is an Engineer. Jane has just been hired to work in publicity. Frank and Terry both want Jane to be their girl. Terry has designed a new carburetor that should bring him fame and money, but he cannot get it to work correctly. Terry and Gadget have tested it for over a year, but it still is not perfected. Emery Motors assigns Frank to help Terry with the carburetor, but Terry is not happy because Frank is an Engineer and is also vying for Jane. They finish the carburetor, and to test it, they enter a car in the Indianapolis 500 race. Terry is not yet satisfied with the carburetor before the big race even though it has passed all the tests.

A playboy takes a job as an assistant district attorney, finds himself up against a tough crime boss and his gang.

In 1840 two rival steamship companies race to see who should have the best cargo between England and America. Two brothers are involved, one on each ship.

Boston Blackie and his pal, The Runt, are ready to board a train for Florida when Blackie gets a telegram from his friend Arthur Manleder asking Blackie to go to Manleder's New York apartment, get $60,000 from a wall safe and fly to Hollywood. Blackie has just removed the money when Police Inspector Farraday and his assistant, Sergeant Matthews arrive and accuse him of robbery. They let him escape so they can follow as they think he knows something about the stolen Monterey Diamond.