A fabulous jewel known as the 'Dark Star' is stolen; a pastor's daughter gets involved, falling into the depths of a spy plot concerning war plans and fortifications...

Lieutenant Bert Hall, an ace American flyer serving in World War I as a member of the French Lafayette Escadrille, is wounded in an aerial battle and forced to land behind enemy lines. Finding his German opponent dead, Hall exchanges uniforms with him and is taken to a German hospital to recover. There he meets his old Kentucky sweetheart, who was unable to escape Berlin when the war broke out. Accompanied by the Countess of Moravia, who claims sympathy with the Allied cause but is actually a German spy, they escape to France in a German plane. Through the countess' duplicity, Hall is accused of betraying the French government and sentenced to be shot, but his American lover uncovers evidence that saves him at the last moment.

After a prologue where we are shown the backgrounds of Wilhelm II and Woodrow Wilson, we see the story of Conrad Le Brett from Alsace-Lorraine. Forced to fight for Germany Conrad, sees soldiers taking girls into a church to rape them and kills one who murders a baby. Shot in the encounter he is taken to a Brussels hospital run by nurse Edith Cavell where he falls in love with American nurse, Amy Gordon. After Edith Cavell assassination and the murder of Conrad’s sister Vilma by the evil Lieutenant Ober Conrad honors her dying request that he go to America and defend Alsace-Lorraine's reputation. Once there he convinces President Wilson that Alsatians should be allowed to enlist. Fighting with the "doughboys," Conrad kills Ober, and after the armistice, returns to Amy.

A farce in which the German Kaiser and the Crown Prince are defeated and made sport of by a plucky American girl and several American prisoners of war.

When Miriam Smith's devoutly religious aunt and uncle insist that she marry pious Simeon Althoff, she answers an ad in a matrimonial newspaper and runs away to New York to meet her correspondent. Upon learning that Miles Sprague, the man in the ad, is coming to claim her, Miriam gets cold feet and begs her experienced friend Kittie Swasher, the hotel telephone operator, for help. When Miles arrives, Kittie pretends that she is Miriam and the three go to a cabaret. Meanwhile, the detectives employed by Miriam's aunt and uncle to bring her home appear and arrest Kittie, thinking that she's Miriam. Simeon arrives soon after and identifies the real Miriam, who is then taken home and locked in her room. Kittie and Miles follow and rescue Miriam, who realizes that she has fallen in love with the man from her ad.