This was to have been Ace's final story with the program. The story was to have been a four part story featuring two rival factions of Ice Warriors battling in 1960s London. The setting at first was to have been a terraformed Mars, but Andrew Cartmel requested it be changed to 1960s London. This story would have also introduced Sam Tollinger, a friend of the Doctor's who would reappear in several stories, and through him lead directly in the next story, Crime of the Century.