Meteors are falling in the English countryside and a poacher finds a strange polyhedron at the site of one of the meteor-strikes. The TARDIS lands on Earth and the Doctor (Jon Pertwee) emerges, falling unconscious. He is taken to Ashbridge Hospital in Epping. Doctors are shocked to find he has two hearts and his blood is not human. Brigadier Lethbridge-Stewart (Nicholas Courtney) of UNIT asks Doctor Elizabeth Shaw (Caroline John) to investigate the meteors, thinking aliens may be responsible. She is sceptical and unhappy to be leaving her work at Cambridge. The plastic polyhedron is a power device for a non-corporeal alien species called the Nestene Consciousness. Normally without physical form, it is drawn to plastic and can create human replicas called Autons. The invaders have taken over a nearby toy factory and plan to reproduce government and public figures. The Auton leader sends out plastic dummies to retrieve the power units.
After recovering in hospital, the Doctor narrowly avoids being captured by the Autons. During the escape, he steals the clothing of an elderly doctor, including a cravat, a jaunty hat, and a cape, which he finds very attractive. He also steals the gentleman’s classic car. This is the scene, following every regeneration, in which the new Doctor finds his style. Using a tracer, he finds his TARDIS where UNIT has taken it. He discovers that the Time Lords have disabled his TARDIS and exiled him on Earth. Despite his new regenerated appearance, he convinces Lethbridge-Stewart that he is indeed the Doctor he knows.
Working with Liz Shaw, the Doctor uncovers the Nestene plot, as the Autons go on a killing spree. He creates an electroshock device that he believes will stop them. UNIT assaults the plastics factory, but the Autons cannot be stopped with gunfire. Sneaking into the factory, the Doctor and Liz find a plastic tentacled creature. The Doctor struggles with the creature (unfortunately, the scene reminds me of an octopus-victim in an Ed Wood movie), while Liz stops it with electroshock. This shuts down all the other Autons. The Brigadier asks the Doctor to stay and help Earth. He agrees to join UNIT, if he is given facilities to repair the TARDIS and a neat vintage car. Liz stays on as his assistant.
This season begins the recording of Doctor Who in colour. From now on, no Doctor Who episodes are permanently destroyed. To cash in on the popularity of James Bond, this earthbound Doctor becomes a martial-arts-fighting dandy with Beatle-boots and Seventies-era frilly shirts, which he wears with somewhat more panache than I did. This first Third-Doctor story is a good one, the walking dummies creepy and scary, and the Brigadier as always perfectly humourless, strait-laced, and delightful. He is now a recurring character.