An unpublished manuscript about a secret prison camp called Poggenberg took the author to Poland. Was it fact or fiction? Norman Davies suggested that the Zachodni Institute in Poznan might know. Maria Weychan and her mother were members of the AK and were imprisoned in the camp for nearly two years, but there was mystery surrounding the 'two women who did not feature on the transport lists'. Were they collaborators, traitors or double agents? It took nearly five years to find an answer. The investigation led into the heart of the Abwehr and Canaris's intelligence network.