The wreckages of three German U-boats are eroding at the bottom of the sea, along with the stories behind their disastrous fate. They are: UC-66, the only U-boat sunk solely by an Allied airplane in WWI off the Isles of Scilly; U-87, rammed by a British patrol boat in the Irish Sea during WWI; and U-480, sunk by a mine in the English Channel during WWII. (To counter Allied sonar, U-480 was coated with a rubber shield codenamed Alberich.) Now, a team of maritime archaeologists race to locate the submarines and solve the mystery behind their deadly demise. 

The aerial bombardment of the Japanese fleet at Truk Lagoon sinking 40+ ships and the Soviet torpedo strike of the German ocean liner MV Wilhelm Gustloff in the Baltic Sea killing 9,000 passengers are two of the most shocking attacks of WWII; now, expert divers explore these underwater graveyards for new evidence of these maritime conflicts.