The German battleship Bismarck was the most heavily armored and advanced warship of its day, yet it was brought down by canvas-covered biplanes and a single jammed piece of steering gear. This episode traces the final 72 hours of the Bismarck, from the sinking of HMS Hood in the Denmark Strait on May 24 to the moment the ship capsized on the morning of May 27. Along the way it examines the psychological pressure on fleet commander Gunther Lutjens, the fatal decision to break radio silence, and the massive British effort that pulled battleships, carriers and cruisers off convoy duty to hunt one ship.

The story unfolds as a chain of small failures: a leaking fuel tank that left an oil slick for an RAF Catalina to follow, a near friendly-fire attack on HMS Sheffield that only failed because of defective magnetic torpedo detonators, and a second Swordfish strike with contact detonators that locked the rudder at 12 degrees in a Force Eight gale. From the night of destroyer harassment with starshells to the point-blank bombardment by HMS Rodney and King George V, the scuttling order, and the rescue cut short by a U-boat alarm, the episode explains how a marvel of engineering became a prison for its crew and why the loss shifted German naval strategy toward U-boats.

• How Lutjens’ mistaken belief that British radar was still tracking him led to a long coded transmission that let the Admiralty triangulate the Bismarck’s true course toward France
• Why obsolete Fairey Swordfish biplanes from Ark Royal flew too slowly for German fire-control predictors, and how the Sheffield near-miss led armorers to switch to reliable contact detonators
• The engineering of the crippled ship: why steering by alternating propeller speeds failed in 40 mph winds and 20-foot waves, and why the Arado float plane carrying the war diary could not launch
• The final battle by the numbers: roughly 2,800 British shells and around 400 hits, the 9:02 a.m. shell that destroyed the bridge and fire control, and the contrast between Rodney’s flat-trajectory fire and King George V’s plunging fire
• The human cost and aftermath: 110 men pulled aboard by Dorsetshire and Maori before the U-boat alarm, only 114 survivors from a crew of over 2,200, the loss of HMS Mashona the next day, and Hitler’s loss of faith in surface raiders