Back at Bletchley, Jericho joins the effort at deciphering contact reports and eventually produces a 'menu' for the cryptanalytic 'bombes' to work upon. He slips out and secretly deciphers the stolen cryptograms with the Enigma settings Hester has obtained. From these he learns the Germans have discovered thousands of bodies buried in the Katyn Forest. The corpses are those of Polish officers who must have been murdered by Britain's ally, the Soviet Union, after it invaded eastern Poland in 1939. Another cryptogram proves to be a list of abbreviated Polish names; he continues deciphering until he discovers a familiar name: "Pukowski, T". He realises this is Puck's missing father, and that Claire had stolen the cryptograms to bring to Puck, her secret lover.