Professor Bernard Quatermass is called upon to investigate a mysterious meteorite shower that has fallen in a rural part of England. When he arrives, he discovers that the meteors contain a strange, otherworldly substance. To his shock, he learns that a nearby factory, ostensibly producing synthetic food, is actually a front for a large-scale alien invasion. The substance appears to be connected to a vast, sinister operation involving infected humans who are working under the control of an extraterrestrial force. Quatermass begins to suspect that the invasion is far more advanced than anyone realizes.

Faced with mounting evidence of the alien threat, Quatermass enlists the help of Inspector Lomax and other authorities. Together, they uncover more about the scale and nature of the invasion, which includes government officials and key infrastructure being compromised. Tension rises as Quatermass and his allies struggle to expose and combat the extraterrestrial plot, racing against time to prevent a complete takeover. Their journey into the heart of this conspiracy challenges their resolve and pushes them to their limits as they confront an unknown and seemingly unstoppable enemy.