The Trygon Factor

Mysterious things happen on the family estate Emberday Hall and the monastery complex located on the same property. Inspector Thompson is murdered during his investigation. The nun Clare O'Connor - the last person he had contact with - is also found dead. Superintendent Cooper-Smith takes over the investigation and follows the trace whether the events in the monastery are connected with a bank robbery in London.

German version: "Das Geheimnis der weißen Nonne"