The Tardis is engulfed by a mysterious web-like substance in space. Breaking free, the Doctor and his companions Jamie and Victoria land in the London Underground system. But a spreading killer mist has meant that London has been evacuated. The Great Intelligence is back – and its robot Yeti are roaming the streets and the underground tunnels. The Doctor, Jamie, and Victoria team up with an army unit working with their old friend Professor Travers to combat the menace. They soon realise, however, that someone in the group must be working for the Intelligence. With time running out, the Doctor and his friends realise they can trust no one…This novel is based on a Doctor Who story which was originally broadcast from 3 February – 9 March 1968. Featuring the Second Doctor as played by Patrick Troughton with his companions Jamie and Victoria. About the AuthorTerrance Dicks worked on scripts for The Avengers as well as other series before becoming Assistant, and later full Script Editor of Doctor Who from 1968. Dicks worked on the entirety of the Jon Pertwee Third Doctor era of the programme, and returned as a writer – scripting Tom Baker’s first story as the Fourth Doctor: Robot. His later script writing credits on Doctor Who included the 20th anniversary story The Five Doctors. Terrance Dicks novelised many of the original Doctor Who stories for Target books, and has written original Doctor Who novels for BBC Books.