Transit

"Maybe time travel fucks with your mind..." 

The Ice Warriors don't appear in Transit, but their presence is felt throughout the story. Set several years after the Thousand Day War (the war between Mars and Earth) and a about fifty years before GodEngine, Transit involves the Seventh Doctor's attempts to stop the alien presence that has taken over the public transit system and the mind the Doctor's new companion, Professor Bernice Summerfield. There are numerous references to events in the Thousand Day War specifically and to the Ice Warriors in general.