The story is told through testimonial flashbacks at a
military tribunal held in Paris after the end of World War II. Its purpose is to investigate and uncover the identity of a traitor reputed to have fed information to
German Occupation forces. In its efforts to find the truth, four witnesses are called to testify: (a) Peter Forrester, an American, ostensibly
OSS, who served with the
French Resistance movement; (b) Maria Corbett, a
Resistance member who posed as a Catholic nun; (c) Marcel Brevoort, a Resistance leader who served with Forrester before and after France's fall; and (d) Major Latrec, the most zealous anti-Nazi in the group, demonstrably loyal to the Underground's cause. Testimonial recall of their unit's activity during the war builds to a surprising revelation. == Cast ==