A Norwegian refugee leads the British in an attack against his country's Nazi invaders.

In 1939, the residents of a peaceful Norwegian fishing village gather to celebrate the wedding of Anna and Gunner Korstad. That evening, as widower Eric Toresen dances with Judith Bowen, the daughter of a British admiral, Bergesen, the town pessimist, worries about the encroaching German forces. After they finish their dance, Eric introduces Judith, who is scheduled to sail for England the next day with her father and brother Robert, to his young daughter Solveig. Soon after Eric bids a melancholy farewell to Judith, Hitler begins his march across Europe and into Norway. After seizing power from the Norwegian government, the Germans proclaim that resistance will be met with death and impose rigid curfews and restrictions on the residents of the fishing village. When Bergesen questions their actions, the Germans arrest him and take him away for questioning. After hoisting the Nazi flag over the village, the Germans proceed to burn objectionable books, confiscate the villagers' supplies and indoctrinate their children. When Solveig returns home from school one day and recites the lesson of German superiority taught her by a Nazi officer, Eric protests to her teacher. In reply, the teacher wistfully speaks of joining the Norwegian resistance movement in England. Soon after, Bergesen, now a broken old man after his experience with the Nazis, returns home. Outraged by the Nazis' barbarism, Eric admonishes the villagers to unite and form an underground resistance movement. Anna, fearing for her life and that of her husband Gunner, pleads to let others fight their battles for them. Gunner joins the resistance, however, and one day is arrested and executed for his activities. In retaliation, Eric stabs the German officer who ordered his execution, then seeks safety for his daughter and takes her to Mrs. Olav's cabin in the hills above the village. Exhausted, Eric falls asleep there and is awakened the next morning by the sound of German trucks. Eric and Solveig hide in a well, and after searching the house, the Germans inform Mrs. Olav that they have taken five villagers hostage, her grandson among them, and will execute them unless Eric surrenders within two days. Entrusting Solveig to Mrs. Olav's care, Eric takes cover in the woods, where he overhears some German soldiers discussing the construction of a secret German airstrip there. Realizing that he must notify the British about the airstrip, Eric asks Johan Garmo to transport him to England in his fishing boat. When Garmo tells Eric about the killing of the hostages, Eric decides to surrender, but Garmo convinces him that he must remain free because his mission is crucial. Agreeing to convey Eric and several others to England, Garmo asks innkeeper Karl Arnesen to join them. After accepting Garmo's offer, Karl informs the Germans of their plans and is given a silent dog whistle with which to summon the German troops once he boards the boat. As the men gather in the woods to meet Garmo that night, Karl's wife Hilma warns Eric of her husband's treachery. Upon casting off from shore, Eric seizes Karl's whistle and pushes him overboard to certain death. Days later, the little boat lands in England and Eric travels to London to tell Admiral Bowen about the airstrip. After agreeing to lead a troop of British commandos to the strip, Eric meets Judith again. When Eric is ordered to immediately fly with Robert, now a soldier, to Scotland, Judith follows him there. On the eve of his mission, Eric proposes to Judith, and after she accepts, he ships out with the commandos. Under Eric's navigation, the British ship sails across the North Sea, up the fjords and to a river leading to the airstrip. As the commandos disembark, Robert dispatches two men to find Solveig. After a prolonged battle with the Germans, the commandos destroy the airstrip and return victoriously to their ship. When the men sent to find Solveig report that she and Mrs. Olav are being held prisoner at the inn, Robert and Eric lead the troops to free her. In the ensuing combat, Eric and Robert are both killed by German bullets, but the commandos overpower the Germans and free their prisoners. As Solveig and the other villagers sail to safety in England, they vow to return home to Norway one day.