Trama

American reporters Helen Warnet and Jed Howard meet on a boat to Shangai unaware that Japan had just invade China and enemy spies are everywhere.

When newspaper reporter Helen Warner exposes the illegal activities of a gang of racketeers, she is threatened by the crooks, and, as a result, is sent by her boss on a vacation to China to avoid danger. On the ship to China, Helen befriends newsreel cameraman Jed Howard, but keeps her profession a secret from him. The two arrive in Shanghai just as war breaks out in North China, and, after seeing Jed depart for the front, Helen reports at the Shanghai office of her newspaper to manager Bob Laird. While getting her credentials to cover the war, Helen meets Chandler, a sinister fellow passenger travelling aboard her ship. Helen's suspicions are raised when both Chandler and Laird insist that Chandler had not been out of the country recently. While Jed and his Chinese assistant, Jimmy Riley, are in the thick of the action, Jimmy sees one of his countrymen fall and attempts to enter the battle, but is subdued by Jed, who rushes him back to Shanghai. En route, they collide with Helen's car. Helen informs Jed that a missionary told her that the Chinese army was routed when a trainload of reinforcements was dynamited by enemies. When Helen and Jed attempt to locate the missionary, they find him murdered. While investigating the mystery, Jimmy is shot and killed by an assassin. An attempt is made on Jed's life, and his assistant, when caught, swallows poison to avoid being captured. Helen, suspecting Laird, finds a secret passageway under his office leading to another office, in which Laird and the others are gathered. Helen and Jed overhear a plot to signal bombing planes to attack a Chinese arsenal. The two are discovered, but escape and turn to a tong, a secret society, with a plan to trap the spies and save the arsenal. Three airplanes are then placed at Jed's disposal. As arranged, Jed goes aloft while Helen and the tong watch the house they suspect is spy headquarters. The city, hearing airplanes overhead, turns off all lights. The conspirators, believing the airplanes to be enemy bombers, shoot a rocket signal to light the arsenal, an act which betrays their guilt and indicates their whereabouts. Helen and the tong capture the spies and the real enemy bombers fly over later to find no illuminated target below. Jed and Helen then return home to be married.