A group of men parachute into Japanese-occupied Burma with a dangerous and important mission: to locate and blow up a radar station. They accomplish this well enough, but when they try to rendezvous at an old air-strip to be taken back to their base, they find Japanese waiting for them, and they must make a long, difficult walk back through enemy-occupied jungle.

The film pivots around the local Norwegian doctor and his family. The doctor's wife (Ruth Gordon) wants to hold on to the pretence of gracious living and ignore their German occupiers. The doctor, Martin Stensgard (Walter Huston), would also prefer to stay neutral, but is torn. His brother-in-law, the wealthy owner of the local fish cannery, collaborates with the Nazis. The doctor's daughter, Karen (Ann Sheridan), is involved with the resistance and with its leader Gunnar Brogge (Errol Flynn). The doctor's son has just returned to town, having been sent down from the university, and is soon influenced by his Nazi-sympathizer uncle. Captain Koenig (Helmut Dantine), the young German commandant of the occupying garrison, whose fanatic determination to do everything by the book and spoutings about the invincibility of the Reich hides a growing fear of a local uprising.