At the dawn of the space age the British Rocket Group launches three astronauts on an experimental mission. Their ship, Quatermass 1, loses radio contact with Earth and later crash-lands. Professor Bernard Quatermass (Brian Donlevy) is one of the first on the scene, and is intrigued to discover that two of the crew are no longer aboard. It soon becomes clear that the mission's sole survivor, Victor Carroon (Richard Wordsworth), is desperately ill - he is rapidly consumed by the parasitic alien organism that killed his fellow astronauts. Followed in 1957 by 'Quatermass 2'.