The inside story of life aboard the deadly Nazi U-Boat that sank forty-nine ships. The history of one of World War II's most successful submarines, U-124, is chronicled in Grey Wolf, Grey Sea , from its few defeats to a legion of victories. Kapitanleutnant Jochen Mohr commanded his German submarine and navigated it through the treacherous waters of one of the most destructive, savage wars the world has known.