On September 6, 1776, Ezra Lee climbed inside a small egg shaped vessel carrying a very large bomb containing 150 pounds of gunpowder. Lee's mission was to attach the time bomb to the HMS Eagle: the flagship of a British fleet that was blockading the harbour during the American revolutionary war. However, no remains or plans of the Turtle survive and Bushnell's tiny sub failed to sink the British ship. A team of wood and metal craftsmen attempt to re-build the mini sub in order to discover if it was capable of attacking the Eagle.