Discusses strategy and tactics and uses re-enactments to show what it was really like to serve in submarines in both the Atlantic and Pacific theaters of action. Looks at stories of some individual boats and their legendary skippers, including Dudley "Mush" Morton, Richard O'Kane and others. Although the U.S. sub fleet had the highest casualties of any branch of the military (22% killed), they also sank more enemy shipping than was sunk by all other forces combined.