Doctor Who season 13

The thirteenth season of British science fiction television series Doctor Who began on 30 August 1975 with the story Terror of the Zygons, and ended with The Seeds of Doom.

This is the second series to feature the Fourth Doctor, played by Tom Baker, with Philip Hinchcliffe producing and Robert Holmes script editing.

Tom Baker continued his role as The Fourth Doctor along with Sarah Jane Smith (Elisabeth Sladen).

Harry Sullivan, played by Ian Marter, departed in Terror of the Zygons and reappeared in The Android Invasion as a guest star.

The season took a transmission break of two weeks over the Christmas 1975 period, between the broadcasts of The Android Invasion and The Brain of Morbius.