Several months before D-Day, the British stage a daring rescue deep inside Germany. Led by British Major Jonathan Smith and including one American, Lt. Morris Schaffer, their mission is to rescue American Brig. Gen. George Carnaby whose airplane was shot down over Germany. Carnaby, one of the architects of the D-Day invasion, is being held in the Schloss Adler, the Eagle's Castle, built high on a promontory and accessible only by cable car. The team successfully parachutes into Germany but lose their radioman in the jump and then a second member of the team within a day. Taken prisoner by the Germans, Smith's true mission is revealed.