Invaders Invisible (short story)

Invaders Invisible was a short story published in Doctor Who Annual 1971. It featured the Third Doctor, Liz Shaw and the Brigadier.

Summary
As the Doctor drives at night towards a UNIT instillation he sees something solid rise up from the moonlit sea. Ten minutes later he stops his car as black mud slides over a wall into the road near him. He gets out and notices something shining in the mud. He feels a sense of drowsiness and, when he touches the mud with his foot, an electric tingle. He runs back to the car, retrieves a metal canister and scoops up some of the mud. At the UNIT base he asks Liz Shaw to look at the sample while he and the Brigadier take six men and a jeep back to investigate. However, when they get back to where the mud had been it has vanished. On returning to UNIT headquarters the Doctor is shocked to find Liz pointing a gun at him. Along with Captain Harvey, she has the Doctor and Brigadier tied up and then she sets out to bring back 'the host'. The Doctor notices that Liz and Harvey seem to be behaving without animation in voice or movement.

Several hours pass until Liz returns with a container. The Brigadier has managed to loosen his bonds and says he will soon put a stop to the mutiny. The Doctor warns him that the 'mutineers' are acting under the influence of something deadly. When he sees Liz scoop bowls of black stuff from the tank and order the soldiers at the base to be inoculated he agrees that it is the time for action. The Doctor overpowers Liz while the Brigadier knocks out Harvey. The Doctor looks at his hand and sees that it is inky black. As the Brigadier watches, the Doctor fights an internal battle against the invader and emerges victorious. He plunges his hand into disinfectant and then notices the mass of black stuff in the tank is trying to flow over the edges.

Captain Harvey rises to his feet and wrestles the Brigadier but the Doctor emerges from a cupboard with an x-ray machine. The captain slumps to the floor and the Doctor tells the Brigadier that the insurrection is over. He x-rays Liz and tells the Brigadier that neither she nor Harvey, nor anyone else they may have touched, will remember what happened. He says that a flying saucer dropped the slime into the sea. It is a mass of viruses that, combined together, can infiltrate the minds of the victims and turn them into a colony or hive for the aliens. He says that the saucer has now gone, its job done, and it will not return.

Characters

 * Third Doctor
 * Liz Shaw
 * The Brigadier
 * Captain Harvey
 * a sentient virus

Continuity
to be added