The action in Decoy follows after Lt. Ned Yorke recovers from his adventures in the book Convoy. It is the story of Lt. Yorke?s participation in a plan to recover a modified Enigma machine from an active German submarine without the Nazi naval command learning about it during the Battle of the Atlantic. With the help of Jemmy and the Croupier, Ned concocts an audacious plan to lure a German submarine into picking up ?stranded? merchant mariners. How Ned gets the Enigma machine and foils the Germans makes a rousing good read.