When the Germans invade Norway their Commandant and the town Mayor confront each other, attempting to maintain civility as far as possible. When the army tries to orgnanize townspeople to work for them sabotage which is at first humorous turns serious, resulting in death on both sides.

George Corell, a general store owner in a small Norwegian mining village, has secretly arranged for the German Army to invade and occupy the town. On the appointed day, Corell sends the town's inhabitants and tiny militia on a picnic, and the German forces, led by Col. Lanser, quickly move in. Six of the militiamen are killed by machine gun fire as they try to repel the enemy, and the stunned townspeople surrender. Lanser interviews Mayor Orden and his wife Sarah, and the town's historian and doctor, Albert Winter, who are outraged to learn of Corell's treachery. Lanser explains that Germany needs the town's iron and warns Orden that the village will be destroyed if the miners do not work hard. The doctor tells Lanser that the Norwegians still have peacetime values, and that it will take time to learn to relinquish their free will. Soon after, Corell visits Lanser, who despises the traitor as much as Orden does. Although Corell has been injured by a thrown rock, he refuses to believe that the townspeople have turned against him. Lanser advises Corell that he would be safer living elsewhere, but Corell insists on staying until he receives orders from Berlin. Lanser, who was a member of the forces invading Belgium and France during World War I, is worried that the villagers will rebel against their oppressors, and his fears are realized when mine worker Alex Morden kills the taunting Capt. Bentick. Alex is put on trial, and his wife Molly begs Orden to spare his life. Orden promises Molly that no Norwegian will sentence Alex to death, but despite Orden's request for leniency, the colonel orders a firing squad to shoot Alex. The squad's leader, young lieutenant Tonder, grows unhappy as the months pass and the occupying forces are treated with increasing hostility. The townspeople also attempt more daring acts of sabotage, even trying to alert the RAF to the mine's location so that it can be bombed. Lanser reluctantly retaliates by arresting and killing villagers at random, even though he knows that each death will make the saboteurs more determined. On the verge of a nervous breakdown, and unaware that Molly is the wife of the man he helped to execute, Tonder visits the young widow and confesses his love for her. Although the equally lonely Molly is tempted to accept his friendship, she remembers Alex and stabs Tonder to death with a pair of scissors. After Molly escapes to Sweden, English planes drop packets of dynamite with instructions on how the Norwegians can best resist the German infiltration. As explosions damaging German operations begin, Corell again visits Lanser and informs him that he has received orders from Berlin to hold Orden and Winter as hostages and execute them if the sabotage continues. Lanser protests, asserting that the executions will fuel stronger resistance, but finally has the mayor and doctor arrested. Orden bravely bids farewell to Sarah and their feisty cook Annie, then discusses the situation with Winter and Lanser. Drawing strength from Socrates' denunciation of his assassins, Orden tells Lanser that a mayor "isn't a man, it's an idea," and that his people will continue to fight for freedom. Lanser then receives word that an important warehouse has been dynamited, and Orden, Winter and the other hostages march with dignity to the gallows. As the men are hanged, the villagers sing of their love for their country, and their song is accompanied by the sound of more explosions.