Munitions worker Barry Kane is wrongfully accused of igniting a fire at the Stuarts Aircraft Factory in Los Angeles, leading to the tragic loss of his best friend, Ken Mason. Determined to clear his name, Barry uncovers that the true arsonist is Frank Fry, the very man who had given him a fire extinguisher that was filled with gasoline instead. With a clue in hand—a letter directed to Fry from Deep Springs Ranch in Springfield, California—Barry heads there, hoping to unearth the truth. Upon his arrival, Charles Tobin, the ranch's owner, denies knowing Fry, but Tobin’s granddaughter gives Barry a telegram indicating Fry's plans to flee to Soda City.
Though Tobin calls the authorities and has Barry arrested, an unexpected turn of events allows Barry to escape by jumping off a bridge just as a rainstorm hits. Seeking refuge from the rain, he finds himself in the home of blind composer Philip Martin. During this brief sanctuary, Patricia Martin, Philip’s niece and a New York model, unexpectedly arrives. While Philip is instinctively aware of Barry's innocence, Pat attempts to inform the police about his presence. This forces Barry to take her hostage for her safety as their car breaks down in the unforgiving California desert. They find salvation in the company of a passing circus.
Eventually, their journey takes them to the eerie ghost town of Soda City, where they discover it to be a hideout for the saboteurs Freeman and Neilson. Barry manages to feign loyalty to the saboteurs, convincing Freeman to provide him with a way to New York City. However, Pat believes Barry has turned rogue and reports him to the authorities. Upon reaching New York, Freeman brings Barry to Mrs. Henrietta Sutton's mansion—where Pat is being held captive by the saboteurs.
Tobin appears, declaring that Barry's identity as a subversive has been exposed by Pat’s uncle. Amidst the scheming of the fifth columnists, Barry and Pat sneak into Mrs. Sutton's lavish society ball. However, when Pat is abruptly seized, Barry is coerced into surrendering himself to Tobin. The following day, the saboteurs, masquerading as newsreel photographers, plot to destroy the battleship U.S.S. Alaska during its christening at the Brooklyn Navy Yard.
In a moment of quick thinking, Barry creates a distraction by activating the fire alarm, which allows him to escape the mansion and thwart the saboteurs' plan to blow up the ship, although the dock itself meets destruction. The saboteurs then seize Barry, taking him to their skyscraper hideout where the police are waiting, having been tipped off by Pat.
In a frantic finale, Fry escapes to a nearby movie theater, but Barry struggles to persuade the police to pursue him. However, Pat bravely follows Fry to the Statue of Liberty, where she contacts the FBI, prompting their urgent arrival. In a nail-biting chase atop the statue's torch, Fry desperately clings to its outstretched hand. Barry attempts to save him, but as Fry's sleeve tears, the murderer falls to his demise, sealing an intense chapter of betrayal and justice.
