The season consisted of four serials and fourteen episodes of twenty-five minutes each. Unlike season 23, there was no overall story arc, and the episode allotment - two four-episode stories, two three-episode stories - would be retained for the remainder of the original series. Notably, the season featured the introduction of new companion Ace, who would be a prominent figure in the spinoff fiction that kept the Doctor Who name alive following its cancellation in 1989 and was the final official onscreen companion until Rose Tyler in the revived series. Unlike the previous regenerations of the Doctor, the Sixth Doctor's happened at the beginning of the season's episode. Colin Baker, who played the Sixth Doctor, would not come back to shoot a few episodes leading up to the regeneration as he felt insulted at being replaced after a short time as the Doctor.