The Doctor Leaving the TARDIS

The TARDIS materialises, in a clearing in a wood. The Doctor, having been forced to regenerate by the Time Lords (see "The War Games"), has been exiled to Earth. As the TARDIS doors open a lone figure collapses onto the ground. He is soon found by UNIT troops and taken to a nearby hospital where his unusual anatomy, including having inhuman blood, confounds the medical doctors. An unscrupulous hospital porter informs the press who then descend on the hospital. As well as the press a very strange looking man also has an interest in these events.

Meanwhile the head of the UK branch of UNIT, Brigadier Lethbridge-Stewart (AKA The Brigadier), is faced with having to deal with not only an unusual meteorite shower but also the report of this strange patient and the sighting of a blue police telephone box in the wood – could this stranger be The Doctor?

The Brigadier decides that a visit to the hospital is required. He is accompanied by newly-recruited UNIT scientist Liz Shaw who has degrees in medicine and physics – as well being an expert in meteorites. The Brigadier though is disappointed to discover that this stranger looks nothing like The Doctor he once knew. However, although the man looks totally different, when he temporarily regains consciousness, he recognises The Brigadier.

The Newly Regenerated Doctor

As The Brigadier leaves the hospital he is unaware that an attempt is made to kidnap The Doctor. The Doctor though manages to escape in a wheelchair, which he then abandons. As he approaches the TARDIS he is shot by a UNIT soldier guarding the time machine. The Doctor is returned to the hospital but it seems that the bullet that hit him was fatal as the medical doctor is unable to detect any brain activity.

The Brigadier returns his concentration back to the meteorites that continue to fall in the area and then mysteriously disappear. He is also approached by an ex-employee of a local plastics factory, who claims he has seen a walking mannequin. Deep within the nearby factory the meteorites are being collected. The meteorites are in fact hollow globes containing the Nestene consciousness, a disembodied alien intelligence with an affinity for plastic. A Nestene agent, Channing, has infiltrated the plastics factory and is using energy from the globes to animate Autons - mannequin-like figures – with the plan to replace key government and public figures with Auton duplicates which will then take over the planet.

The Brigadier Being Watched

Back at the hospital The Doctor recovers and, when the medical staff are pre-occupied, he escapes, stealing the clothes and the car of a visiting consultant, who has just arrived at the hospital to take a look at the strange patient. The Doctor arrives at the UNIT HQ where he manages to convince The Brigadier that, despite his change in appearance, he is the same man who aided him before to defeat the Yeti and then the Cybermen. The Brigadier is finally convinced and so tells The Doctor all about the meteorites. The Doctor agrees to help. However, he is secretly only interested in retrieving the TARDIS key which The Brigadier has custody of. The Doctor persuades Liz to get the key for him but he soon discovers, when he tries to depart in the TARDIS that has been brought to UNIT HQ, that he can no longer operate his time machine and so is trapped on Earth. He therefore has no choice but to continue to help The Brigadier.

Meanwhile, UNIT troops have found one of the meteorites but, while en-route with it to the UNIT HQ they are intercepted by an Auton causing them to crash, it is stolen. Despite this setback another meteorite – containing the swarm leader - has been found by a poacher and is being kept in a metal trunk at his home. When UNIT discovers this they arrive at his house – but they are not alone as an Auton is also searching for the globe. A battle commences but the Auton is unaffected by the bullets fired at it. Instead the Auton reveals a gun nozzle within its hand and starts to shoot at them. Luckily for the UNIT troops the Auton is suddenly and unexpectedly recalled.

With the ability to finally investigate a whole intact meteorite The Doctor realises that there is some form of intelligence in the globe, and, with information from the distraught Ransome about the moving mannequins, he starts to piece together what is happening. However, it is not long before Major-General Scobie, who is in charge of the regular Army, is replaced by an Auton which then gains access to the UNIT HQ so as to retrieve the final energy unit. With all the energy units now collected, by the Nestene consciousness, other Autons, who have been distributed all over the country, come alive. To the horror of passes by shop dummies start to move and burst from department store windows, killing anyone who gets in their way.

An Auton

Back at the UNIT HQ The Doctor, with the help of Liz, manages to create a device that he believes will disable the Autons. And so when UNIT attacks the plastics factory The Doctor and Liz make their way inside. There they encounter an octopus-like creature inside a glass tank that the Nestenes have created that will be used to conquer the Earth. The Doctor's weapon though does not work. However, while The Doctor struggles with the creature, Liz discovers the problem, fixes it and so destroys the Nestene Intelligence. This results in neutralising all the Autons as they are all part of the Nestene consciousness.

Despite there being no current threat from the Autons The Brigadier is concerned that they may return and so The Doctor agrees to stay and help UNIT in exchange for facilities to help him repair the TARDIS and a car like the sporty antique roadster he commandeered when he made his escape from the hospital. He also requests that Liz stays on as his assistant.