Pilot John Dooley and his crew of four are flying an Air Force mission in a Douglas C-47 Skytrain (the military version of the DC-3). They experience icy conditions in the uncharted wilderness near the Quebec-Labrador border. Dooley is a former airline pilot who had been pressed into duty hauling war supplies across the northern route to England. Unable to make radio contact for bearings, they land on a frozen lake far from settled country and can only provide an approximate position to rescuers. Compass readings were unstable in this region. Dooley must keep his men alive while waiting for rescue in the extreme winter cold with temperatures plummeting to -70 degrees Fahrenheit and limited food. At headquarters, Col. Fuller gathers fellow airmen, close colleagues of Dooley, who are determined to find the downed crew before the men succumb to hunger and the cold. The search pilots experience frustration and fear when their initial attempts are unsuccessful. From the sketchy data they have, it seems Dooley went down on the far side of a range of mountains that doesn't even appear on their maps. In the face of an approaching storm, they are unsure as to what their final attempt should be. A wrong decision will doom the missing crew. The downed crew are able to use a hand-cranked generator to send a weak signal that will hopefully be picked up.