Errol Flynn fought World War II all over the world without ever leaving the United States. For this film, he took the battle to Canada as a Mountie who uses his German background to infiltrate a group of Nazi saboteurs planning to bomb the St. Lawrence Seaway. In real life, Flynn was kept from military service by a variety of health problems Warner Bros. chose not to publicize for fear it would tarnish his swashbuckling image. When he collapsed on the set during a bout with tuberculosis, they only stated that he had an upper respiratory ailment. They were quicker to capitalize on his statutory rape trial. After swearing he loves only his fiancée (Julie Bishop) in the film, he turns to the camera and quips, "What am I saying?" For all his problems, Flynn threw himself into his World War II actioners, on his best behavior while doing his bit with the war effort. It helped that he enjoyed working with director Raoul Walsh, who keeps the whole plot moving briskly. With daredevil stunts and mountain scenes shot in Sun Valley, ID, the film lives up to the advertising calling it "a mighty avalanche of adventure."

By Frank Miller