In 1931, explorer Hubert Wilkins set out to reach the North Pole not by ship or plane but underwater, in a decommissioned US Navy submarine built in 1916 and rechristened Nautilus. The vessel had no heating, no insulation, and machinery already worn out by fifteen years of service, yet the plan called for it to dive beneath the polar ice cap itself. The film traces the expedition through archival photographs, ship's logs, and expert interviews, following the crew as engine failures, freezing conditions, and a damaged diving mechanism turn the voyage into a fight for survival rather than a scientific triumph. It covers the political backdrop too, with sponsors and the press expecting a historic breakthrough while the submarine barely holds together. The Nautilus never reaches the Pole, but the attempt becomes one of the more remarkable near-disasters of polar exploration, and the film treats its failure as seriously as it would a success.