On the volcanic planet Sarn, Turlough recognizes several Trion artifacts that point to Malkon (the Chosen One among the Sarn people) being his own brother. Meanwhile, Peri flees from Kamelion who has almost been entirely possessed by the Master.

Starring:

Elisabeth Sladen, Frazer Hines, Jacqueline Hill, John Levene, John Scott Martin, Jon Pertwee, Katy Manning, Nicholas Courtney, Pat Gorman, Patrick Troughton, Peter Davison, Tom Baker, William Hartnell, William Russell

Genre:

Adventure, Drama, Sci-Fi