Sickan, the leader of the criminal Jönsson gang is incarcerated in a mental institution, attended by Dr M.A. Busé, who admire a handbook in crime that Sickan has been writing. Blackmailed by the nefarious banker Wall-Enberg, Dr Busé and Sickan's partners Vanheden and Dynamite-Harry execute Sickan's plan of stealing the valuable Black Diamond of the Romanovs from the National Museum.
Ulf Brunnberg
Ragnar Vanheden
Björn Gustafson
Dynamit-Harry
Peter Haber
Dr. Max Adrian Busé
Birgitta Andersson
Doris
Elias Ringquist
Lillis
Björn Granath
Lohman
Pontus Gustafsson
Andersson
Bernt Lindqvist
The Chief of Police
