Canadian Richard Hannay, residing in London, meets secret agent Annabella Smith immediately following a shots fired incident. She asks to go home with him. Back at Hannay’s flat the mysterious woman confides that she fears for her life and is on a critical mission relating to protecting state air ministry secrets. Later that night assassins murder her. Believed by the police to be her killer, Hannay is forced to go on the run and flees to Scotland in a desperate attempt to see Annabella’s mission through before it’s too late. Along the way he chances upon beautiful Pamela, who unwillingly becomes his accomplice in the mission.
On a train headed for England a group of travelers is delayed by an avalanche. Holed up in a hotel in a fictional European country, young Iris befriends elderly Miss Froy. When the train resumes, Iris suffers a bout of unconsciousness and wakes to find the old woman has disappeared. The other passengers ominously deny Miss Froy ever existed, so Iris begins to investigate with another traveler and, as the pair sleuth, romantic sparks fly.
Derrick De Marney finds himself in a 39 Steps situation when he is wrongly accused of murder. While a fugitive from the law, De Marney is helped by heroine Nova Pilbeam, who three years earlier had played the adolescent kidnap victim in Hitchcock’s The Man Who Knew Too Much. The obligatory “fish out of water” scene, in which the principals are briefly slowed down by a banal everyday event, occurs during a child’s birthday party. The actual villain, whose identity is never in doubt (Hitchcock made thrillers, not mysteries) is played by George Curzon, who suffers from a twitching eye. Curzon’s revelation during an elaborate nightclub sequence is a Hitchcockian tour de force, the sort of virtuoso sequence taken for granted in these days of flexible cameras and computer enhancement, but which in 1937 took a great deal of time, patience and talent to pull off. Released in the US as The Girl Was Young, Young and Innocent was based on a novel by Josephine Tey.