The Master

At a circus, a horse box appears out of thin air and a bearded man dressed in a black suit emerges. He introduces himself as ‘The Master’ to the circus owner, Luigi Rossini. The Master then hypnotises Luigi Rossini thus enabling him to get the circus owner and his crew to break into the National Space Museum and steal a sole surviving Nestine energy unit that is there on loan from UNIT. The Master then takes the energy unit to a radio telescope facility, killing the technician on duty. After hooking the energy unit to the radio telescope a signal is sent into space and this results in the Nestene Consciousness once more inhabiting the energy unit.

At UNIT headquarters, The Doctor is introduced to his new assistant, the rather overexcited Jo Grant, who has joined UNIT as a replacement to Liz Shaw, who has returned to Cambridge. Despite his initial apprehensions, at not getting a scientist to replace Liz, The Doctor cannot bring himself to tell the enthusiastic Jo that he doesn't want her help.

Reports of the theft of the Nestene unit and the act of sabotage at the Beacon Hill radio telescope facility lead The Doctor, The Brigadier and Jo to investigate. On arrival, The Doctor encounters a fellow Time Lord who warns him that his old enemy, The Master, is on Earth. The Time Lord also alerts The Doctor that The Master has left a booby trap bomb in the control room. Pre-warned The Doctor manages to prevent the bomb from exploding. He also discovers the murdered technician who has been shrunk to a tiny size – a hallmark, which The Doctor recognises, as being the work of The Master.

The Master's TARDIS

After The Doctor explains all about The Master, The Brigadier orders the search of all plastic factories in the hope of finding and The Master. Meanwhile, The Master has hypnotised the owner of a plastics factory, and the production of Nestene-controlled plastic Auton products begins. This includes a deadly chair and a very ugly looking troll-like doll.

Jo, after being excluded from the carrying out any of the searches decides to do some investigating of her own. More by luck than judgement she stumbles upon the correct plastics factory. However, she is caught and hypnotised by The Master, and made to return to UNIT headquarters with the box that originally contained the Nestene energy unit. Now though it contains a bomb intended for The Doctor. On realising that Jo has been hypnotised The Doctor is alerted to the danger just in time and throws the box out of the window where the bomb explodes harmlessly. The Doctor then breaks Jo's trance but she is unable to tell them where The Master was based.

'I Am The Master'

With the help of Captain Mike Yates, The Doctor learns that The Master’s TARDIS is located at the circus. He goes there along with Jo, who had stowed away in Bessie, and is able to steal the dematerialisation circuit from The Master's TARDIS – hoping that he can use it in his own TARDIS and so escape from his exile on Earth. They are then attacked by a mob of circus workers but are rescued by two policemen. But they turn out to be Autons in disguise. The Doctor and Jo are eventually rescued when The Brigadier with some UNIT troops arrive. Back at UNIT HQ, The Doctor discovers that The Master's dematerialisation circuit, that he stole, does not work in his TARDIS. His action however, means that The Master is now trapped on Earth as well.

Then UNIT become aware of an increasing number of strange and unexplained deaths that are suddenly occurring across the country. At first there does not seem to be any link between them until it is discovered that the first two victims have connections with a plastics factory – the same factory that Jo originally discovered. When The Doctor and The Brigadier visit the plastics factory they find it deserted barring a plastic daffodil on the floor and an Auton in the safe.

Back at UNIT headquarters another attempt is made on The Doctor’s life. This time a newly installed telephone cable comes alive and tries to strangle him. Luckily The Brigadier comes to his rescue. The Doctor then discovers that the daffodils can be activated by short wave radio signals and that they spray a fast-hardening plastic over the nose and mouth of anyone close enough, causing death by asphyxiation. UNIT realise that it is these deadly daffodils that are responsible for most of the reported deaths and that they are being distributed by the Autons. Disguised in fancy dress they are travelling around the country, in a bus, giving them away free to members of the public in a fake promotional campaign. On realising that the Nestenes can put life into anything made of plastic The Brigadier orders an air-strike to destroy the Auton’s bus to prevent the distribution of any more of the daffodils.

The Doctor

On realising that his TARDIS’ dematerialisation circuit has been stolen The Master arrives at UNIT headquarters and threatens to kill Jo if The Doctor does not hand it over. Jo, however, accidentally blurts out about the airstrike on the bus. This prompts The Master to take both The Doctor and Jo hostage so as to prevent The Brigadier from destroying the bus. The Master then reveals to them that he intends to activate the daffodils by radio impulses from the Beacon Hill radio telescope facility. When The Brigadier and UNIT arrive a battle begins with the Autons. This allows The Doctor and Jo to escape from the bus. While the battle between UNIT and the Autons continues, The Doctor manages to convince The Master that the Nestenes will have no further use for him once they arrive. The Master, realising that The Doctor is right, helps him repel the Nestene Consciousness back into space causing all the Autons to collapse.

Distracted by the sudden demise of the Autons, The Master is able to return to the bus. He then tricks UNIT into shooting the owner of the plastics factory, who is disguised as The Master. This enables the real Master to drive off in the bus. However, with the dematerialisation circuit in The Doctor's hands, The Master is still trapped on Earth and The Doctor confesses that he is quite looking forward to him turning up again.