After Quatermass (John Robinson) discovers that everyone in the committee meeting also have marks from being exposed to the meteorite gas he informs Broadhead (Rupert Davies).  Broadhead misunderstands and thinks that there may be potential sabotage involved in the food processing.  Quatermass on the other hand is sure that whatever is happening is being done to the people not the food.  Quatermass leaves the meeting.  When he returns later with Fowler (Austin Trevor) it appears that Broadhead has now been marked and is denying that there is anything wrong with the plant.

Fowler knows of someone who has been to the plant.  He makes arrangements with him and Quatermass to meet Rupert Ward (Derek Aylward).  Ward is a public relations officer.  He has the authority to inspect the plant and occasionally takes people out with him.  Using Ward’s pass, the three of them gain entrance to the plant.  Quatermass notes that there are large domes containing various pressurized gases.  Since the structure of the plant is identical to his plans of a moon base, he summarizes that the purpose of the domes is to create habitation for some life form that is not oxygen based.

Ward slips away and investigates one of the domed structures.  He slips and is covered with a black corrosive slime.  Ward dies telling Quatermass that this substance is what is in the domes, not food.  Quatermass takes some samples of it.  Fowler and Quatermass escape from the plant before they can be discovered.  He takes the samples back to the Rocket Group to have them analyzed.  He finds out that the domes contain a poisonous substance and not food.  At least not human food.   

In the meantime, Dr. Pugh (Hugh Griffith) discovers that the meteorites are coming from an asteroid, and the asteroid is headed toward Earth.  Each time the asteroid nears Earth it sends out the meteorites.         

Dr. Who stories that were directly influenced by the Quatermass series include “The Web of Fear” 1964, “The Invasion” 1965, “Spearhead from Space” 1966, “The Ambassadors of Death” 1967, “Inferno” 1968, “The Daemons” 1969, “The Seeds of Doom” 1070, “Image of the Fendahl” 1971 and "The Lazarus Experiment" 2007.