The planet Peladon has applied to join the Galactic Federation, and The Doctor is mistaken for the chairman of the committee sent to assess its application, while Jo is taken for an Earth princess, with the mythical curse of Aggedor apparently striking chancellor Torbis dead, The Doctor must discover who is desperate to stop Peladon joining, but soon he is sentenced to death and his only Allies seem to be Jo and the Ice Warrior Delegates.

The Second Doctor and Jamie arrive on what appears to be a space station called the "Wheel in Space" it's here that they meet Zoe Herriot a young parapsychology librarian, The Doctor hits his head concussing him leaving Jamie and Zoe to defend off the Cybermen from taking over "The Wheel in Space."

The TARDIS narrowly avoids becoming engulfed in a cobwebby substance in space. It arrives in the London Underground railway system, the tunnels of which are being overrun by the web and by the Great Intelligence's robot Yeti. The time travellers learn this crisis was precipitated when Professor Travers, whom they first met in the Himalayas some thirty years earlier, accidentally caused one of the Yeti to be reactivated, opening the way for the Intelligence to invade again.

The adventures of The Doctor, a time-traveling humanoid alien known as a Time Lord. He explores the universe in his TARDIS, a sentient time-traveling spaceship. Its exterior appears as a blue British police box, which was a common sight in Britain in 1963 when the series first aired. Along with a succession of companions, The Doctor faces a variety of foes while working to save civilizations, help ordinary people, and right many wrongs.