This is a fantastic adventure war film, a story of derring do with the tension and atmosphere that submarine films have to have and it culminates in a neat land based battle. John Mills plays the commander of a British submarine sent out on a mission to hunt a German battleship. They eventually become the hunted as German destroyers try and sink them and by the time we get to that there's been the introduction to the lives, loves and friendships of the crew members so that the audience is caught up in their desperate attempt at escape and survival. They have to come up with a daring plan to get home leading to a clever final section of the film that's as good as any war film of any age. What is especially entertaining about this film is it seems to be less about flag waving and more focused on being a good war story and like all these films made during and immediately after the war there's the marvellous nostalgic images of England in the 40s. This is an exciting and superb war film, one of the great submarine combat films and well worth seeking out.