A German-American father, loyal to his new U.S. home, finds himself on opposite sides with his son in the wartime conflict between Germany and America. The son becomes involved with German agents plotting against U.S., and the father must decide between his son and his adopted homeland.
Returning from France after the war, John Tabor informs Palma May of her brother's death and offers the penniless girl his help, but she refuses it, preferring to work as a cabaret dancer. Later, John and Palma meet again, marry, and go west to manage a lumber camp, as instructed by John's wealthy father, Jarvis Tabor. Displeased by John's choice of wife, the elder Tabor tests the couple with difficult living conditions, which eventually discourage Palma, and she accepts the party invitation of Keith Merwyn, manager of the cabaret where she starred. Meanwhile, Merwyn effects a disturbance among the lumbermen, endangering John.
Secret Service officer Richard Paget receives a letter from his twin brother John imploring him to take over his identity after he commits suicide, so that Richard can subvert the plans made by the airplane company which John had financed, to make defective planes for the United States to use in the war.
During World War I, the beautiful and patriotic Leslie Selden is courted by two ardent admirers: Jack Wynn, a young man not yet taken by the draft, and Dr. Wolff, a Danish scientist who, in reality, is a German agent. When Jack learns that Wolff is masterminding a plot to bomb several munitions factories and destroy the water system in New York City, he goes to the spy's home and confronts him.
Loyal slave of the aristocratic Dabney family, Dan is overjoyed when Raoul becomes engaged to Northerner Elsie Hammond and his sister Grace becomes engaged to Elsie's brother John. When the Civil War breaks out, the heartbroken Hammonds return North and John joins the Union army. Raoul joins the Confederacy, but his vindictive overseer, Jonas Watts, becomes a Union officer. Watts takes Grace prisoner, but before he can act on his desires, John rescues her.
The hero is a young soldier who is in love with two girls simultaneously. While on the battlefield, the soldier learns that one of his sweethearts has committed suicide. Only temporarily taken aback, he begins to dream of the blissful domesticity which he will enjoy with the other girl upon his return.
During the early War of Resistance Against Japan in Baiyangdian, Hebei, the Yanling Squad, led by Communist Party member Hei Lao Cai, conducted effective guerrilla warfare. Yang Xiaomei, fleeing abuse from her husband Zhang Jinlong, joined the squad and developed feelings for farmer Niu Dashi. Zhang Jinlong, unable to change, defected to the Japanese. As Japanese sweep operations intensified, Xiaomei, Dashi, and Zhang Jinlong faced different paths in the conflict.
Phillip Gresson is in the employ of the British secret service, while heroine Judith is a spy for the Enemy. Hoping to gain possession of the usual Secret Plans, Judith pretends to be in love with Phillip. Only after nursing the seriously wounded Phillip back to health does Judith come to the realization that she genuinely loves him.