British Captain Terence Stevenson accepts an assignment even more dangerous than his everyday job of defusing undetonated bombs. Fluent in Romanian and German and having studied chemical engineering, he's parachuted into Romania to assume the identity of Captain Jan Tartu, a member of the fascist Iron Guard. Tartu makes his way to Czechoslovakia to steal the formula of a new Nazi poison gas and sabotage the factory of its manufacturing.

Third and final film in the 'Inspector Hornleigh’ series of comedy-thrillers. Inspector Hornleigh (Gordon Harker), disappointed at not being handed an important spy case, is assigned by Scotland Yard to an army barracks to investigate the mundane thefts of supplies from the stores. This accidentally leads Hornleigh and Sergeant Bingham (Alastair Sim) to a nest of fifth columnists when his dim-witted assistant carelessly talks to a girl in the cafeteria – and that night, news of Hornleigh and Bingham’s arrival is embarrassingly transmitted back to Germany.

David Phillips (Patrick Macnee) is running down the darkened streets of London's Limehouse district, pursued by two men with guns. He finds a public phone and puts a call through to Dick Barton (Don Stannard), but before he can report, a shot rings out. Barton must piece together what Phillips found out that got him killed. Phillips had been assigned to protect Professor Mitchell (Percy Walsh) and his new development, a ray capable of exploding any unstable element aboard an aircraft in flight. Mitchell has been targeted for kidnapping by Serge Volkoff (Meinhart Maur), a foreign agent from Eastern Europe, as part of a larger, much more sinister plot to destroy England and cripple Western Europe. Complicating matters further is that Mitchell's daughter (Joyce Linden) has also been kidnapped, and Barton must contend with Volkoff's crafty female companion Anna (Tamara Desni).

Nutbourne College, an old established, all-boys, boarding school is told that another school is to be billeted with due to wartime restrictions. The shock is that it's an all-girls school that has been sent. The two head teachers are soon battling for the upper hand with each other and the Ministry. But a crisis (or two) forces them to work together.

Forever England gives John Mills his first leading role as Brown. Born after a brief affair between his mother and a naval officer, he joins the Royal Navy during the First World War. There his bravery and marksmanship keeps a German ship in port so a British ship can sink it. He becomes a hero, but at what cost?