British Captain Terence Stevenson (Robert Donat) accepts an assignment even more dangerous than his everyday job of defusing unexploded bombs. Fluent in Romanian and German and having studied chemical engineering, he is parachuted into Romania to assume the identity of Captain Jan Tartu, a member of the fascist Iron Guard. He makes his way to Czechoslovakia to steal the formula of a new Nazi poison gas and sabotage the factory where it is being manufactured.

Robert Donat
as Captain Terence Stevenson, aka Jan Tartu

Valerie Hobson
as Maruschuka Lanova

Walter Rilla
as Inspector Otto Vogel

Glynis Johns
as Paula Palacek

Phyllis Morris
as Anna Palacek

Martin Miller
as Doctor Novotny

Anthony Eustrel
as German MP Officar

Percy Walsh
as Dr. Willendorf
CinemaSerf
There were quite a few of these medium-budget films made - not quite as propaganda, but serving to bolster the morale in Britain in the depths of WWII. This is one of them. Robert Donat plays a fictional British intelligence officer charged with seeking out and destroying a secret Nazi factory that ...