Cowley appears to have stolen two canisters of a new nerve gas and is recorded trying to sell them to German Otto Hahn. Bodie and Doyle are asked to keep a surveillance on him though he asks them to shadow an Arab called Malik, which they suspect is purely to keep them off his trail. They trace him to a country mansion, where they are caught by Hahn's men but Cowley claims not to know them. Is he really guilty of treason or has he devised a plan to catch the real traitor?
—don @ minifie-1