Jewel thieves, murder and a manhunt swirl around a sailor (Bonar Colleano) off a cargo ship in London.

Quatermass is the director of an important scientific base, where he builds nuclear rockets for the colonization of the Moon. A strange fall of meteorites in a nearby village leads to the discovery of a huge base under a strict military control, officially a factory of artificial food. Quatermass reveals that the factory is actually breeding alien creatures.

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.