Synopsis: Professor Quatermass, still shook up from London's refusal to proceed with his project to colonize the Moon, is intrigued by the mysterious traces that have been showing up on his radar - meteorites crashing down?. Following them to the place where they should be landing he finds a destroyed village, a mysterious factory too close to his designs for the Moon colony for comfort, and some strange, aerodynamic objects containing a mysterious, ammonia-based gas that infects one of his assistants.