Ross and Mallory dive down to the wreck site of 36-gun Nelsonian frigate HMS Amethyst, a legendary battle cruiser, launched in 1799, which proved one of the most successful and prolific of the Napoleonic wars. Ross makes an incredible find using an underwater metal detector, and the historic item reveals why the ship was such a potent weapon of war but also gives clues as to how and why it sank. It leads Ross, Mallory, and Neil to the 16th century Minera Tavern for a story of trickery and kidnapping by the Royal Navy.