The TARDIS materializes in 1966 in London.  The Doctor and Dodo visit the Post Office Tower and they meet Professor Brett.  His computer WOTAN (Will Operating Thought ANalogue) is an AI computer and is to be connected to other major computers around the world.  WOTAN determines that humans are inferior and that it rule over them.  It begins the construction of War Machines by hypnotizing human workers.  The Doctor captures one of them and reprograms to destroy WOTAN.  Dodo decides to remain on Earth and the Doctor re-enters the TARDIS alone.  Professor Brett's secretary Polly and Ben Jackson follow him inside just before he leaves.