Ella Muggins (Elsa Lanchester) is a Camberwell charwoman who is the widow of a regimental sergeant major. One day during the London Blitz, she relates to her friends a story about a "magic eye" charm that her husband obtained during his Army service in India that protected him from all harm. Whilst cleaning her attic, she goes through her husband's effects and finds the charm that she absent-mindedly puts in the pocket of her skirt.
During an air raid, she is caught in the middle of the street with a delay-action bomb. One air raid warden tells her to run, another to lie down. She does the latter and survives the explosion, though she is helped to the shelter in a daze. As she recovers, she is convinced that her husband's "Magic Eye" charm has protected her. She asks a friend what she would do if she were totally invulnerable. Looking up to the street being bombed, her friend replies that she would go to Germany and "give that Mr. Hitler what for". Ella leaves the shelter, unconcerned about the bombs exploding around her, as she sets out to do just that.
Stowing away on a British merchant ship, Ella is discovered by the crew, who think having a woman aboard is bad luck; subsequently, a German bomber sinks the ship. Ella reaches France in a lifeboat, where the other survivors are quickly captured by the Germans. Ella works her way across France and Germany, pretending to a deaf-mute cleaning woman. She shares a train compartment with German Captain Franz Von Weber (Gordon Oliver). Franz's fiancee's uncle, Frederick Walthers (Lloyd Corrigan) arrives, and she is asked to leave the compartment. Both men are members of the anti-Hitler German resistance. Walthers informs Franz that Grete (Lenore Aubert), his fiancee, has been arrested. Franz is determined to rescue her.
Ella gets herself hired as a cleaner in the Reich Chancellery when she convinces Lieutenant Bosch that she is deaf and dumb. Luckily for her, she sees Bosch's reflection when her back is turned to him and shows no reaction when he shoots his pistol to test her. She is working in Sturmfuehrer Dietrich's office when the British traitor Herr Joyce (Gavin Muir), "Lord Haw", comes to complain about his treatment. Dietrich is unconcerned, as Joyce's usefulness is rapidly diminishing. On his way out, Joyce slips on a bar of soap Ella has carefully placed. Ella also overhears that Grete is being held in Mobit Prison.
When Franz tries to see Dietrich, Ella writes the message "Grete Mobit" on the floor. Noticing Ella's brush says "Champion: Made in England", Franz later hears the supposedly deaf and dumb woman singing in English, and realizes Ella is not who she seems. Outside, she lends him her Magic Eye to rescue Grete. Franz is able to have Greta released, but it is actually a ploy by Dietrich; he has the couple followed in hopes they will lead him to other members of the German Resistance.
Inside Hitler's private office, Ella rehearses what she will say to him, but Dietrich is eavesdropping on the intercom. Lord Haw-Haw enters and begs Ella to help him escape from Germany. Both are arrested, as are Frederick, Franz and Grete. After Dietrich gives Ella back the eye, the Royal Air Force bombs the Chancellery. Frederick is killed, but Ella, Franz and Grete take advantage of the confusion to escape to an airfield, where Franz steals a bomber. They fly to England and land by parachute.
Feted as a heroine, Ella shows a reporter her husband's chest where she found the amulet, but discovers many more in a box labeled as souvenirs of a glass blowers' exhibition.
As credited, with screen roles identified:
In August 1943, no less than six Hollywood films about Adolf Hitler or with Hitler as a title (i.e. Hitler's Children, Hitler – Dead or Alive, The Strange Death of Adolf Hitler, The Hitler Gang) were in production. Principal photography took place from late August to mid-September 1943. Originally filmed as Dangerous Journey, the title was changed to Passport to Adventure perhaps due to the similarity to Warner's Desperate Journey then to Passport to Destiny. The production was rushed through "before some soldier beats Elsa to Hitler".
Two actors were "borrowed" from other studios: Gordon Oliver came from David O. Selznick Productions and Lenore Aubert from Samuel Goldwyn's company to appear in the film. Ray McCarey, the brother of Leo McCarey, was signed on a contract to Republic Pictures after the film.
For the climatic escape scene, the studio again used the Capelis XC-12 transport that was on the backlot, this time painted to resemble a Luftwaffe bomber.
Passport to Destiny was intended to be a comedy but despite the best efforts of its star, the contrived scenario of a Hitler assassination are described as doomed by a "screenplay (that) was quintessential tommyrot, undiluted by even the smallest amount of intelligence or common sense." Only Lanchester's charm "made it bearable with her unique histrionic abilities." A more recent critique notes, "The movie is indeed charming and amusing; at least, it is for the length of time that it plays its story for silly comedy. Unfortunately, but not unexpectedly, the movie starts to take itself seriously at the half-way mark ..." Film critic Leonard Maltin described it as a "tidy programmer".