Publisher's Synopsis
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 and his companions, Jamie and Victoria, team up with an army unit working with their old friend Professor Travers to combat the menace. The group's new commanding officer is Colonel Lethbridge-Stewart - whom the Doctor will come to know far better in the years ahead. As the Doctor begins to wonder if the Great Intelligence has planned everything simply to trap him, he also realises 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.
