'The Doctor responds to a distress call, calculating the odds that he should have received it at all are astronomical. He arrives outside a door and tosses an apple into a force field. The fruit is destroyed so he throws in a battery. The energy field is absorbed by the battery which the Doctor pockets for use later. He enters a hall which is full of an astonishing array of machinery, covering all sizes from small to vast and all complexities from clockwork to anti-matter fusion. At the centre is a tall box containing a man. This man is attached to the box by a variety of wires, rods, tubes and metal cages. A scalpel is about to cut into his chest. The Doctor produces his sonic screwdriver and a leather pouch containing small tools. With these he begins to disconnect the man from the mechanical devices that have been attached to and inserted into his head, body and limbs. As he works at this the Doctor draws the man into conversation. It turns out that the Doctor has freed this man from a similar predicament several times before but never understood who the victim was or how he came to be captured in this way. This time he begins to get some answers. The man knows that the Doctor is a Time Lord. He himself is from a race that exists outside time and the universe. However, he has seen that machinery is capable of developing a life of its own. He has taken on physical shape to hold back the machinery before it expands to fill the universe, but each time he does this he is overtaken by the machines which try to mechanise his body. Each time this happens he sends out a distress call that the Doctor answers. The first time the Doctor came, the machine was the size of a spaceship; this time it is the size of a small planet. This time, unlike others, the man has a robotic arm which attacks the Doctor. Holding it in check, he allows the Doctor to escape. The Doctor returns to the TARDIS and removes the mechanical devices which are already attaching themselves to it. He turns to the man, still part-machine, and says farewell until the next time. The man says that he thinks that the next time will be the last. The Doctor says he had better go away and prepare himself for this.'
Source: drwhoguide.com (http://www.drwhoguide.com/whotrip26.htm). Sighted: 20/5/11