Jönssonligan & den svarta diamanten

Blackmailed by the banker Wall-Enberg, Dr. Max Adrian Busé (Peter Haber) joins Ragnar Vanheden (Ulf Brunnberg) and Dynamit-Harry (Björn Gustafson) to steal the Romanovs' Black Diamond from the National Museum. The plan comes from Sickan, their leader, who is locked in a mental institution where Busé is his doctor. Hans Åke Gabrielsson directs the first Jönsson film without Gösta Ekman, so Vanheden has to lead the job himself.