The British Rocket Group, headed by the taciturn Professor Bernard Quatermass, launches its first manned rocket into space. Shortly thereafter, all contact is lost with the rocket and its three crew: Carroon, Reichenheim, and Green. The large rocket later returns to earth, crashing into an English country field.
Quatermass and his assistant Briscoe arrive at the scene, along with the emergency services. Opening the rocket's access hatch, the space-suited Carroon stumbles outside; inside, there is no sign of the other two crew members. Carroon is in shock, only able to say the words "Help me". He is taken to hospital while Quatermass and Briscoe investigate what happened to the rocket and its two missing crew.
It quickly becomes evident that Carroon has been altered by something he encountered in space; he can absorb any living thing with which he comes in contact. When he smashes a potted cactus in his hospital room, absorbing it, his right hand and then his arm begins to mutate. Not knowing this, Carroon's wife, Judith, hires a private investigator to break her husband out of the secured hospital. The escape is successful, but Carroon then kills and absorbs the private investigator. It does not take long for Judith to discover what her husband has become, and Carroon soon flees from his horrified wife.
Inspector Lomax of Scotland Yard initiates a manhunt to find the missing Carroon. Hiding out at the London docks, he encounters a little girl, leaving her unharmed through sheer willpower. Instead, Carroon heads for a nearby zoo where he absorbs many of the animals. By now he has become a completely mutated creature. Quatermass and Briscoe track the Carroon-creature to Westminster Abbey, where it has crawled high up on the metal scaffolding inside. From his examination of tissue samples taken from Carroon, Quatermass concludes that some kind of alien has completely taken over and will eventually release reproduction spores, endangering the entire planet. With the assistance of a television crew working at the Abbey, Quatermass succeeds in killing the Carroon-creature by electrocution.
The threat eliminated, Quatermass quickly walks through the Abbey, preoccupied by his thoughts. He ignores all who ask questions. Marsh, his other assistant, approaches and asks "What now"? Never breaking stride, Quatermass offhandedly replies, "I'll need your help. We start over again". He quickly leaves Marsh behind, walking into the London night.
Where is Quatermass walking through?
the Abbey