Stephen, who was a schoolboy fencing champion, is able to disarm the boys. He is told that Operation Silver Thread is to happen the next day, and is to involve the Damocles space-station. One of the crew of the Damocles, Lee Wan, has an accident whilst working outside the space-station, and is blasted into space. John, Stephen and Elizabeth use a matter transporter to take Chris's transit van into space. They rescue Lee Wan, and take him back to the Lab. Stephen returns to the school, and that night is initiated into the Doomsday Men. Operation Silver Thread begins: General McLelland and his troops arrive at the Damocles in a space ship. Pretending to be the relief crew, they seize control of the station.
Aired: 22 Apr 1974