Synopsis: Fed up of noisy aeroplanes at the North Pole, Santa Claus has moved to another planet where he is making toys for Christmas. Santa has had many requests from children for model TARDISes and the Doctor decides to help by using a device that he calls his 'magic box'. However, Santa's Christmas preparations are threatened by the evil Demon Magician and it is up to the Doctor, John and Gillian to save the day.
Synopsis: The Doctor witnesses the kidnapping of nuclear physicist Simon Trent and his young son. Giving chase, the Doctor is himself captured and taken to an island belonging to the apparently alien General Steelfist. Both Trent and later the Doctor are transported to a space station orbiting the Earth. There they are forced to construct a nuclear device with which Steelfist intends to blackmail the world. However the Doctor becomes suspicious of the mysterious Steelfist and discovers that the space station is in fact the top of a lighthouse close to the island. With the help of old beachcomber, Arnie Babbs, the Doctor and Trent escape. But is Babbs the friend that he appears to be?
Synopsis: The Doctor shelters from an attack on his mind in the TARDIS where he identifies the source as being an alien spacecraft on the fringes of the solar system. Travelling to London, the Doctor intends to warn the Minister of Defence about the imminent invasion. However, the Doctor discovers the minds of the entire population of Earth have been neutralised by the approaching Zeron invaders. Teaming up with an unaffected American tourist called Nick, the Doctor uses the resources of the Post Office tower to counteract the Zeron mind control. Fearful of looking foolish if the Doctor should be wrong, the British Government refuse to alert the world to the threat of the Zeron invasion. With the help of Nick's disc jockey cousin Jed, the Doctor broadcasts his own warning over the radio. As the Zerons once again bombard the Earth with their mind-control ray, the Doctor leads his friends to the safe depths of the London Underground. However, the Zerons are aware of the Doctor's refuge and take steps to neutralise the threat he poses towards their conquest of Earth.