A quirky war film for various reasons, this one. A Nazi submarine crew are raiding North Atlantic shipping when their submarine is destroyed near the Canadian coast. The crew of survivors - led by a curiously cast Eric Portman - take over an Hudson's bay Company post frequented by a French-Canadian Laurence Olivier and Finlay Currie - a redoubtable Scot who is determined not to to stand for this "invasion". What follows is a sightly haphazard series of stories depicting their attempt to make it back to the Fatherland - by just about every means of transport - barring an hot air balloon - known to man at the time. The last half hour picks up the pace cleverly - with a typically civilised performance from Leslie Howard, as the survivors near their goal, demonstrating that the pen may well be mightier than the sword before a final encounter with Raymond Massey. The cast behind the camera is just as notable - Freddie Young and David Lean (editor) work on Emeric Pressberger's story, under Michael Powell's direction to bring the full effects of the wonderful Canadian scenery; light/shades and hues - as well as a good, taut dialogue - much less trite than in some early, more propagandist efforts.