Professor Bernard Quatermass (Brian Donlevy) is busy trying to drum up government support for his moon colonization project but is distracted by hundreds of meteorites striking Winnerden Flats. He investigates with his colleague Marsh (Bryan Forbes). They find a huge complex under construction, strikingly similar to his moon colony plans. An undamaged meteorite shaped like a rocket releases gas, leaving an odd V-shaped mark on Marsh’s face. Black-uniformed guards with machine-guns and V-shaped marks knock down Quatermass and order him to leave, then take Marsh away.

Quatermass contacts Inspector Lomax (John Longden) of Scotland Yard, who puts him in touch with Vincent Broadhead (Tom Chatto), a member of Parliament who is suspicious of Winnerden Flats and the numerous shipments coming in. Quatermass and Broadhead join a tour of the facilities, which ostensibly makes artificial food. Broadhead slips away from the group and Quatermass finds him dying, covered in black slime.

Shot at by guards, Quatermass leaves to meet Inspector Lomax. Quatermass thinks the factory really is making food, but not for humans. It is to provide a home for small alien creatures living in the domes. They report this, but the commissioner of police has one of the V-shaped marks himself, and the aliens may already be in control of the government. Then they go to journalist Jimmy Hall (Sid James, mostly known for the Carry On films) who is sceptical but wants to see the facilities. They receive a hostile reception from locals, until one of the meteorites crashes through the roof, injuring popular barmaid Sheila (Vera Day). Hall telephones the press and is gunned down by guards. The villagers march on the complex and barricade themselves in the pressure control room.

Thinking that Earth’s atmosphere must be poisonous to the aliens, Quatermass sabotages the life-support system. Hs assistant Brand (William Franklyn) launches a rocket at an asteroid thought to be a staging point. The small aliens combine to create huge 100-foot-tall creatures that burst out of the domes. The asteroid is destroyed, the aliens are exposed to Earth’s atmosphere, the creatures die and the humans bearing the V-shaped marks are set free. They have no memory of being under alien mind-control.

The film (called Enemy from Space in the U.S.) was produced by Anthony Hinds of Hammer Films, directed by Val Guest, based on Quatermass II, a TV series written by Nigel Neale. The Quatermass Xperiment had been a major success for Hammer Films, and they purchased the rights to make a movie of the sequel series even before it aired. Val Guest again used cinema verité techniques to make it seem like a news story. It received mixed reviews. Nigel Kneale was unhappy with the aggressive acting style of Donleavy, and with his drinking, which was excessive. Quatermass 2 is believed to be the first film sequel numbered with Arabic rather than roman numerals. Strangely, it was shot in color and released in black-and-white. Unfortunately, Hammer released The Curse of Frankenstein at the same time, stealing their own thunder. The third film of the trilogy, Quatermass and the Pit, was not made until 1967.