The Final Game (unproduced TV story)

✅ The Final Game was an unproduced serial intended to end Season 11. It would have revealed that the Doctor and the Master were actually brothers, explaining why the Master never sought to actually kill the Doctor. Ihe story would have ended with sacrificing his life for the Third Doctor, followed by his regeneration. However, the episode was never produced due to the death of Roger Delgado, so Planet of the Spiders replaced this story as the final episode for Jon Pertwee.

Legacy
Several elements from this episode have been recycled throughout the years. The Master did eventually directly cause the Fourth Doctor to regenerate in Logopolis, and was the indirect cause of the Tenth Doctor's regeneration in The End of Time. The possible fraternal relationship between the Master and the Doctor was teased in Smith and Jones and then firmly dismissed in The Sound of Drums.