I really would like to see an entire Doctor Who season that has the Doctor visiting former companions (who both the character and their actor is still alive) each having one adventure with said companion in said episode. My proposition for the reason why the Doctor decided to do such a tour is because in the preceding season, a former companion went rogue and went up against The Doctor as that season’s main antagonist, resenting The Doctor for essentially abandoning them. (I am aware that there was a story in the comics that had Adam Mitchell come back as a prominent antagonist resentful of the Doctor after the events of The Long Game, but for this scenario the former companion gone rogue will not be Adam) The Doctor would eventually defeat said former companion but felt guilty for the way they turned out. As much as the Doctor does not check up on old friends, this debacle with a former friend turned enemy gave them a wake up call regarding the people they left behind.…