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.