As WWII raged across Europe and the Pacific, one branch of the U.S. military went quietly about its business, moving with such secrecy that it was dubbed the "Silent Service". The elite submarine sailors endured an unique type of battle--with little chance of escape if disaster struck, the submarine itself often became a steel coffin. WWII comes alive through a moving tapestry of letters, diaries, color film and photographs unearthed from archives and personal collections.