Principal photography did not go well; a number of incidents slowed production. One of the huskies that was key to a scene bit Morgan, opening up a gash on his hand. Cagney, in an uncharacteristic move, decided to forgo a stunt double and play the scene himself in which his character is struck by a whirling propeller. At first things proceeded smoothly, but when it came time for him to fall into the lake, he overdid it and suffered a real concussion, putting the 10-day shoot at North Bay, Ontario farther behind schedule. Weather was a constant challenge, and with the need to ensure continuity, small scenes became unnecessarily complex; as a result, a typical shooting day lasted almost into the night. One 30-second scene with all the principals running along the dock took an entire day to complete, with Cagney, Hale, and Tobias barely able to stand at the end of filming. With a Hollywood production in their midst, North Bay residents became such a persistent nuisance that the crew reverted to sending messages out of the location site by homing pigeons.