'The Interrogation' (tx. 5/2/1969) Written by Dennis Spooner, directed by Cyril Frankel

Concerned by Craig's disappearance, Richard and Sharron go to see Tremayne, their boss at Nemesis. Craig is held in an octagonal cell. He is covered in sweat, yet the wall thermometer says the temperature is only 20 degrees. He fills a cup of water and places it inside a wall cabinet. He tries to reach an air vent above his bed, but suddenly feels vertiginous, recalling an operation in Rome when he nearly fell from a rooftop. The interrogator asks him why he didn't fall in Italy. Craig turns and sees that the Interrogator is speaking from behind one of the walls, which has now become semi-transparent. The interrogator tells Craig that he has been drugged and that he will be recalling a number of past events. The interrogator wants to know what happened during the Rentford case in Hong Kong. Craig claims not to know what he is talking about.

Craig wakes feeling cold, even though the thermometer says the temperature hasn't changed. The water in the cup from the cabinet is frozen, however. The interrogator congratulates him on seeing through the thermometer, a device to disorientate prisoners. Craig passes out again after another bout of questioning.

Later, the interrogator plays back a tape recording of Craig apparently providing details of his mission. Craig denies it and the interrogator suggests he is having memory lapses. Craig drinks water from the tap, too late realising that it is drugged. Sharron and Richard tell Tremayne that they now know where Craig is.

The interrogator enters the cell. Craig's mental state is altered and he now believes that he is back in Hong Kong. The interrogator wants Craig to reveal specific details of the mission, which aimed to reduce the threat of Chinese experiments on insects. Craig sees through the charade and unsuccessfully tries to strangle the interrogator. Realising that the interrogator was in the room with him and must have somehow got out again, he looks for a button to release him. He finds it and gets out of the room, crosses the hall, and enters Tremayne's office. The interrogator is the head of Nemesis security, troubled by unexplained gaps in many of Craig's reports. Tremayne lets Craig leave and closes the case. Outside the office, Richard tells an angry Craig that he and Sharron couldn't help, as they would have had to reveal the secret of their special powers.