As UNIT soldiers enter the cave systems, and the Silurians unleash a deadly plague that could wipe out the human race, the battle for planet Earth begins. This novel is based on "The Silurians", a Doctor Who story which was originally broadcast from 31 January-14 March 1970, featuring the Third Doctor as played by Jon Pertwee, his companion Liz Shaw and the UNIT organisation commanded by Brigadier Lethbridge-Stewart.