Jesper (Gary Cooper) is working on the Manhattan Project – developing the atom bomb. He is co-opted by the OSS to help with the war effort. The US needs to frustrate Germany’s efforts to develop nuclear armaments. Jesper quickly becomes a secret agent working with the Resistance in Switzerland and Italy. The plan is to smuggle out a reluctant German bomb scientist who hates the Nazis but won’t leave because they are holding his daughter captive. With the help of Italian Resistance courier Gina (Lilli Palmer), Jesper attempts to reunite father and daughter and get them to America.

Fritz Lang left Germany for Hollywood in the mid-1930s. He was soon to leave behind the excesses of German expressionism yet subverted popular movie conventions at every turn. To call Cloak and Dagger a wartime espionage caper would be unfair. The plot is full of unexpected twists. Coop may seem too old and stiff for this action role but he is the still centre around which the story revolves. And there’s plenty going on – submarines, aircraft landings, narrow escapes and (inevitably) a love story. There’s also a realistically grisly hand-to-hand killing of an enemy agent in the lobby of an apartment building. It’s done in silences with just the counterpoint of an oompah band playing in the street outside.

This was Lilli Palmer’s introduction to Hollywood. She is a fine (if underrated) actor, always watchable. Here, she is both the hardened gun-toting fighter in a beret and the vulnerable woman who has seen and experienced awful things.

The film was made not long after the end of World War II when memories of wartime hardships were still strong and it lacks much of the brash gung-ho jingoism of later war films. Cinematography is by the great Sol Polito and score is from Max Steiner; both of whom worked in the 1942 picture Now, Voyager.

Available on Blu-ray Mon 27 Jan 2020