Following the devastating attack on Pearl Harbor, the United States entered World War II in December 1941 weakened and outnumbered. With the Pacific battleship fleet decimated by the Pearl Harbor attack, it was up to the feisty and heroic sailors of the US Submarine Force to halt the sweeping Japanese invasion across the Pacific.

Part One: Dark Days -- Wave after wave: Sunday, December 7, 1941 -- Execute unrestricted submarine warfare -- The Philippines: Monday, December 8, 1941 -- Meet the Seawolf -- Seawolf's narrow escape -- The overwhelming forces of the unknown -- Fearless Freddie's daring foray -- Christmas retreat -- Part Two: Brave Men and Terrible Torpedoes -- The bravest stand -- Unlikely heroines: Lucy Wilson and Canopus -- Angels on board -- Sink 'em all! -- Ned Beach: reluctant submariner -- Trigger turns it around -- Surrounded! -- A long, hard year for Seawolf -- Wahoo: an unpromising start -- Part Three: Here Comes the Wahoo -- Mush the magnificent -- Off the map: the unknown waters of Wewak -- The approach -- Down the throat -- A mighty roar -- Wahoo on the attack -- "Good hunting" -- Part Four: The Fightingest -- Dick O'Kane's ice-cream machine -- Stowaways -- Tang makes her mark -- The sea was all ours -- The last, terrible torpedo -- Wolf pack: avenging the Wahoo -- Peace be now restored: 1945.