We watch the last half of “The Five Doctors”, the 20th anniversary special that posits the eternal query: “If Tom Baker can’t be bothered to show up, is it really all that special?” As we ponder that question, the Doctor encounters (yet doesn’t recognize) his childhood bestie, the Doctor encounters phantom companions he shouldn’t know that they shouldn’t recognize him, the Doctor encounters a clumsily-plot-necessary Sarah Jane Smith, the Doctor encounters unused filmed footage, all whilst the then current Doctor saves the day after encountering all that prior stuff (spoilers...?). My brain still hurts trying to make sense of the plot more that forty years after the original airing.