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.
as Ragnar Vanheden
as Dynamit-Harry
as Dr. Max Adrian Busé
as Doris
as Lillis
as Lohman
as Andersson
as The Chief of Police
as Wall-Enberg
as Biffen Johansson
as Busé's secretary
as Count Romanoff
as Guard
as Guard
as Jailer
as Patient
as Patient
as Keeper
