How can a super-size hunk of heavy metal, packed to the gills with fragile humans, dominate an underwater world where the pressure is so intense it could crush you to death in seconds? Focusing on the latest-generation submarine, the USS Texas, as well as other international subs, Super Sub tells the story of this incredible invention. Through exclusive access to training missions, CGI and recreation, we'll show how today's submarines defy the imagination: they dive deeper, are quieter (and deadlier) and are capable of feats that would amaze even science fiction writers. We also investigate what happened in some historic accidents and show how new technologies seek to prevent future calamities.