In 1931, Britain’s most advanced submarine collided with a cargo ship off the coast of China and sank. Three hours later, six sailors surfaced, barely conscious. They were the first men ever to escape from a sunken submarine using a proto-scuba device. Their story hit headlines and went on to inspire a feature film. The miraculous escape changed marine safety forever. But their names, and their submarine, gradually sank into obscurity.

Historian and scuba instructor Steven Schwankert, who splits his time between Beijing and Atlantic Highlands, NJ, was looking for nearby wrecks to dive when he found HMS Poseidon on a list of unexplored sites. This shadow diver's six-year search for the submarine started as a private obsession, but went on to challenge official accounts of the escape, and bring together the lost pieces of a story that touches on the history of Britain and China in the 1930s, the 1970s and the present day.

The film will have its world premiere on Monday, June 3, 2013, in Middletown, NY, as part of the Hoboken International Film Festival.