• Air date: 10 Sep '66 43 episodes
      The fourth season of British science fiction television series Doctor Who began on 10 September 1966 with the 1st Doctor story The Smugglers and, after a change of lead actor part-way through the series, ended on 1 July 1967 with The Evil of the Daleks. For the first time, the entire main cast changed over the course of a single season.
  • List of Episodes (43)
    • 1. The Smugglers (1)

      10 Sep '66
      The Doctor discovers Polly and Ben aboard the TARDIS shortly before the ship arrives in 17th century Cornwall, where the local churchwarden gives the Doctor a cryptic message shortly before being murdered.
    • 2. The Smugglers (2)

      17 Sep '66
      Pike is convinced that the Doctor knows the location of Avery's treasure while Polly and Ben try to convince the locals they were not responsible for Longfoot's murder.
    • 3. The Smugglers (3)

      24 Sep '66
      Polly and Ben are placed in the custody of Blake, who reveals he also has his suspicions about the Squire, while the Doctor and Kewper are forced to team up to escape from Pike's ship.
    • 4. The Smugglers (4)

      01 Oct '66
      The Doctor and his friends are at the mercy of Cherub, who is now seeking Avery's treasure for himself, while Pike prepares to attack the village.
    • 5. The Tenth Planet (1)

      08 Oct '66
      In 1986 a new planet appears in the Solar System which turns out to be a long-lost twin of Earth's named Mondas. Its inhabitants are the Cybermen.
    • 6. The Tenth Planet (2)

      15 Oct '66
      The Doctor's warnings are ignored and the Cybermen take over the base, hampering the crew's efforts to help Zeus IV.
    • 7. The Tenth Planet (3)

      22 Oct '66
      With the Doctor out of action, it is up to Polly, Ben and Barclay to stop Cutler using the Z-Bomb and devastating half the world.
    • 8. The Tenth Planet (4)

      29 Oct '66
      The Cybermen take over the base again, apparently to stop the humans using the Z-Bomb, but then the Doctor realises they intend to use it themselves to destroy Earth.
    • 9. The Power of the Daleks (1)

      05 Nov '66
      The TARDIS arrives on the Earth colony of Vulcan where the newly-regenerated Doctor assumes the identity of an Earth Examiner.
    • 10. The Power of the Daleks (2)

      12 Nov '66
      While the Doctor worries about the inert Daleks in the capsules, Lesterson makes plan to reactivate one of them.
    • 11. The Power of the Daleks (3)

      19 Nov '66
      The Doctor fails to convince the colonists of the danger posed by the Daleks and soon the other two are also reactivated.
    • 12. The Power of the Daleks (4)

      26 Nov '66
      With Polly being held prisoner by the rebels, the Doctor and Ben decide to investigate them, while Lesterson discovers the Daleks are reproducing.
    • 13. The Power of the Daleks (5)

      03 Dec '66
      The Doctor and Quinn attempt to escape in order to stop Bragen using the Daleks to take over the colony.
    • 14. The Power of the Daleks, Episode Six

      10 Dec '66
      With Bragen having taken over, the Daleks trick the rebels into turning them loose and only the Doctor can stop them wiping out the entire colony.
    • 15. The Highlanders, Episode One

      17 Dec '66
      The Doctor, Polly and Ben arrive in 1746, in the aftermath of the Battle of Culloden, and are captured by a group of Highlanders shortly before they themselves are captured by redcoats.
    • 16. The Highlanders, Episode Two

      24 Dec '66
      Polly and Kirsty capture Lieutenant Ffinch to try and enlist his help while the Doctor tricks Gray in order to escape.
    • 17. The Highlanders, Episode Three

      31 Dec '66
      With the Highlanders imprisoned aboard Trask's ship, the Doctor attempts to expose Grey's plan.
    • 18. The Highlanders, Episode Four

      07 Jan '67
      Ben manages to join up with the Doctor, Polly and Kirsty and together they work to free the Highlanders from Trask's ship before Grey sells them into slavery.
    • 19. The Underwater Menace, Episode One

      14 Jan '67
      The TARDIS materialises on a deserted beach where the Doctor and his friends are captured by primitive warriors and taken to the fabled city of Atlantis.
    • 20. The Underwater Menace, Episode Two

      21 Jan '67
      While Ara tries to save Polly from being turned into a Fish Person and Ben and Jamie try to escape from the mines, the Doctor discovers the full extent of Zaroff's plans.
    • 21. The Underwater Menace, Episode Three

      28 Jan '67
      The Doctor and Ramo are sentenced to be sacrificed to the goddess Amdo and must escape to put a stop to Zaroff's plan.
    • 22. The Underwater Menace, Part Four

      04 Feb '67
      With Zaroff's plan nearing completion, the Doctor and Ben realise the only way to save the world is to destroy Atlantis.
    • 23. The Moonbase, Episode One

      11 Feb '67
      The TARDIS arrives on the Moon in the year 2070.When Jamie is injured, the other travellers are forced to seek the help of a moonbase afflicted with a space plague.
    • 24. The Moonbase, Episode Two

      18 Feb '67
      The Doctor and his friends attempt to convince the Moonbase crew that the Cybermen are responsible for the disappearances and find a cure for the plague.
    • 25. The Moonbase, Episode Three

      25 Feb '67
      The Cybermen take over the Moonbase and begin using the Gravitron to attack Earth but Polly, Ben and Jamie come up with a way to fight back.