Ross Kemp visits an old family pub and finds out about his great grandfather, who served in the Merchant Navy and was shipwrecked three times. It inspires him to dive down with maritime archaeologist Mallory Hass on the wreck of WWII cargo ship, the James Eagan Layne, and try to recover its military supplies. His dive in the south Devon waters is cut short by a terrifying kit failure. Determined to make amends he heads out to dive on HMS Amethyst, a legendary 18th century warship that fought for Britain’s trade routes during the Napoleonic Wars. Underwater in south Devon, Ross and Mallory find a remarkable artefact that helps explain why the Amethyst was such a successful warship. Over a final drink at Plymouth’s historic Minerva Tavern, Ross, dive supervisor Neil Brock and Mallory toast the end of his diving adventure.