Planet of Fire

An alien beacon draws the Doctor, a young American girl and her archaeologist father to an explosive adventure on the volcanically active planet Sarn.  Together with the Doctor's assistant, Turlough, and Kamelion, they discover a planet in danger of incinerating itself and a population divided on how to appease the volcano god.  But the planet itself holds dark secrets about its true purpose, and even the Doctor's traveling companions may not be what they seem.  Yet an even more sinister danger arises when the Doctor learns that a bizarre accident has brought the Master to Sarn as well - and the volcanism that threatens the planet holds for him the promise of salvation!

• "Planet of Fire" features the return of The Master (now becoming an annual event).

• This story also sees one companion leave and another one join.  Turlough departs at the end of the story as Peri (played by Nicola Bryant) continues to travel with the Doctor.

• Kamelion, last seen in his introductory story "The King's Demons" is written out of the series.  He never appeared between his introductory and departure stories because of constant technical problems with the robot prop.

• "Planet of Fire" is highly rated among many fans.