This is a novelization of the fifth serial of the sixth season of Doctor Who, which was first broadcast over six episodes in January through March of 1969. Terrance Dicks wrote the adaptation of the teleplay which he wrote in uncredited collaboration with Brian Hayles. The story features The Doctor in his second iteration, and he is joined by long-time companion Jamie McCrimmon, an 18th-century Scotsman, and Zoe Heriot, a 21st-century librarian, mathematical genius, and astrophysicist. This is one of the longest of Dicks' books, and has a more polished feel than most of the others. The story is set on a Lunar station and in a London museum in the future 21st century. The story concerns the ice warriors, militant Martians who are sending poisonous pods to Earth to make it habitable for their invasion and inhospitable for humans. Instantaneous matter transference has replaced all other forms of transportation on the planet, and interest in space exploration has died. Earth is subject to controlled weather. The Doctor finds a way to destroy the seed pods (water? Too simple... he must've just watched The Day of the Triffids on TARDIS TV...) and, in a particularly bloodthirsty twist, lures the Martian fleet into the Sun. Zoe is written as being particularly strong, being intelligent and calm when the male characters panic. This is one of the better adventures of the second Doctor, even though the scientific points weren't especially convincing, even for the time a half-year before the Eagle landed.