Following World War II the United States government implemented a top secret program placing military personnel into a high-pressure situation inside a training submarine. This test was designed to assess their ability to make quick decisions and to determine how well they cope when facing a demanding situation. But due to an "unfortunate incident," the entire operation was shut down and the submarine was covertly dumped to the bottom of the ocean.
You and your team of treasure seekers, while searching a desolate coastline, unexpectedly come across this submarine which has mysteriously resurfaced. Hoping to discover the find of a lifetime, you climb inside. But once aboard, the entry hatch slams shut, machinery begins to whir, and a feminine voice speaks through the darkness. "Is that you, Captain Penrose? Welcome back. Training sequence initiated."