Inferno

Premise: UNIT have been assigned to provide security for an experimental operation, nicknamed the Inferno. The Doctor is also present as a UNIT observer but is secretly siphoning off power.

Notes: The original draft did not feature the parallel universe aspect of the story, this was instead written in later as it was felt that the original idea would not be enough to sustain seven episodes. While Douglas Camfield is the only director credited, Barry Letts took over from episodes three to seven after Camfield suffered a minor heart attack. To stop his illness become widely known because of the damage it might do to his career, Camfield was the only one credited. This is the last story to feature Liz Shaw as it was felt that she did not fulfill the role of a companion, which is to ask questions to that the audience can understand what's happening. This worked at well for Caroline John as she was pregnant at the time however she did not find out why she was dropped until years later.

Verdict: One of the most gripping Doctor Who stories there is with the tension never dropping and the ever present sound of the drill makes for a great atmosphere. The parallel universe aspect is very well realised and Nicholas Courtney is very enjoyable as a villain. With all actors on top form and an almost flawless script with decent special effects, it is undeniably one of the best serials out there 10/10