English nurse Edith Cavell is matron in a small private hospital in German-occupied Brussels during WWI. When the son of a recently deceased patient escapes from a German prisoner-of-war camp, Cavell aids him to reach Holland and safety. This leads to Cavell, a local noblewoman, the grandmother of the escaped prisoner-of-war, and others to form an organization to help Belgian, French, English and other soldiers escape as well. Eventually the Germans become aware of what's happening and take action.

At the outbreak of World War I, English nurse Edith Cavell is in charge of a nursing home in Brussels when she and Mme. Rappard help Mme. Rappard's grandson Jean escape from the invading Germans. Jean flees to the border and is taken to Holland on a barge operated by Mme. Moulin. Inspired by Jean's plight, nurse Cavell, Mmes. Rappard and Moulin and their good friend, Countess de Mavon, perfect a system whereby they smuggle defenseless escaped prisoners into Holland. Their network is exposed when Lieutenant Schultz of the German army poses as an escaped prisoner and presents evidence that brings nurse Cavell to trial before a German military court. Despite pleas and warnings that her execution will trigger worldwide condemnation, no leniency is shown and nurse Cavell is put to death.