An entertainer pretends to join the army and can’t get out, meets a French waitress, is accused of spying, escapes, and is returned to the front.
Actor Jimmy Canfield (Joe E. Brown) performs as a soldier to sell Liberty bonds, but Col. Harper asks why he does not fight. Jimmy says he has flat feet. His fiancé Mary Harper (Beverly Roberts) calls him a slacker and wants him to enlist. Jimmy’s valet Hobson (Eric Blore) has joined the army and tries to make Jimmy angry to fight; but Jimmy just laughs. Bernice (Winnie Shaw) threatens Jimmy with breach of promise, and to escape he says he joined the army. Jimmy marches with the troops but is not allowed to leave.
In France Jimmy tries to sleep on the ground with soldiers. He gets up, and a terrified private asks him shoot his toe so he can go back to his family; but Jimmy nearly shoots his own toe. Hobson is a sergeant and teaches Jimmy to fight without a gun. In a bar Yvonne (Joan Blondell) hides Jimmy from an officer, who molests her. Jimmy hits him, and the officer brings back men to arrest him; but a higher officer tells him to drop the charges after she says what happened. Jimmy and Yvonne sing “For $1.25 a Day.” Jimmy stays with her and her stepfather Pierre (Robert Barrat), who keeps pigeons. Jimmy performs as a Frenchman, but he is arrested for releasing Pierre’s pigeons to the enemy.
Two prisoners with Jimmy are given their last meal and are taken away to be shot. Jimmy drinks with a captain but throws his drinks away and gets the captain’s uniform so that he can leave the prison; but he is ordered on to a truck going to the front. Jimmy is ordered to take out a machine gun nest. In his underwear Jimmy finds a German helmet of an officer. He puts on a coat and tells the Germans to retreat. Jimmy picks up a machine gun and then shows them jujitsu; but he is knocked out. The three Germans refuse to leave. Because Jimmy is not mad, other Germans go with him. He promises them wine, food, and girls. They are attacked and taken prisoners. Col. Harper orders Hobson to arrest Jimmy in front of Mary, Bernice, and Yvonne. Hobson tells Jimmy the charges against him. Jimmy prepares to be shot but is commended in French for capturing Germans. Then he kisses Yvonne.
This farce satirizes the world war and suggests that if people did not get (go) mad, they would not kill each other.