It took a supertanker like the U.S.S. Manhattan, assisted by a nimble icebreaker, the Canadian John A. Macdonald, to realize the dream of centuries: the navigation of a commercial sea lane through the Arctic channels. This is a record of that historic expedition, filmed in colour from both ships and from a reconnaissance helicopter. Commentary by ships' navigators and observers, and shipside sounds of formidable sea ice groaning, straining and cracking make this an adventure rarely seen on film.