Quatermass (John Robinson) sees a mark on Dillon’s (John Stone) face just as the guards from the factory arrive. The guards, who seem to have similar marks, take Dillon away while Quatermass is told to leave the area. Quatermass comes across a vagrant (Wilfrid Brambell) who tells him that a year ago the area had been a nice little village. Then the village was bulldozed, and the plant was built. Not far away they made a prefab town, called Winnerden Flats, where the workers from the plant live.
Quartermass finds Winnerden Flats and tries to get information on what happened to Dillon. He talks to the head of the camp committee, the organization that runs the plant. Quatermass gets nowhere and with the man except being threatened to have the guards called on him. While he is there, he sees a child (Sheila Martin) that seems to be ill. She also has a similar mark on her like the one Dillon has.
Still searching for answers Quatermass goes to London to Scotland Yard. Scotland Yard tells him they have no jurisdiction and sends him to the ministry. Fowler (Austin Trevor) at the ministry tells him is has to do with making synthetic food. Fowler calls Vincent Broadhead (Rupert Davies). Broadhead is an MP who has been making his own inquiries about the plant. He found that there are similar plants in Siberia and Brazil. Broadhead takes Quatermass to a meeting of committee members that represent the plant. The committee members appear to be in a daze. Broadhead addressed the head biochemist, Stenning (John Miller). Then Quatermass notices that Stenning bears the same mark as Dillon, the guards and the child.
Nigel Kneale created the Quatermass character in 1953 while he was a staff writer at the BBC. He was assigned the job of creating a six-part serial to run in July and August. His leading character’s original name was Professor Charlton. Kneale decided he wanted something more memorable. Kneale was a native of the Isle of Man. On the island, surnames that began with “Qu” were common. He picked Quatermass from a London telephone directory. Kneale chose Bernard as his leading characters first name in honor of the British physicist and radio astronomer, Bernard Lovell.