It was during this season that the Doctor cut ties to UNIT (after Terror of the Zygons, the Brigadier would not appear again until Mawdryn Undead in 1983, and The Seeds of Doom marked the last occasion to date that the Doctor was explicitly said to be working for UNIT - as opposed to working with them as occasions warranted). Several of the serials in this season, particularly Pyramids of Mars and The Brain of Morbius, are among the best-known of the 1970s-era storylines. Though it was aired as a part of Season 13, Terror of the Zygons was actually filmed as part of the previous season; this holdover allowed the series to switch back to an autumn season start.

Season 13 Episode 1 - Terror of the Zygons (1)

Scotland, the near future. Something is smashing oil rigs off the Scottish coast, and UNIT have been called in to investigate. The Brigadier summons the Doctor to Earth to help in the investigation, but it soon becomes clear some kind of alien presence is at work... Air Date : 30th-Aug-1975  Read More

Season 13 Episode 2 - Terror of the Zygons (2)

The Zygon traps the Doctor and Sarah Jane in a decompression chamber while Harry is taken to the aliens' underwater ship. Air Date : 6th-Sep-1975  Read More

Season 13 Episode 3 - Terror of the Zygons (3)

The Doctor and the Brigadier begin to realise who the Zygon imposters among them are while Sarah Jane discovers a secret tunnel to the underwater ship. Air Date : 13th-Sep-1975  Read More

Season 13 Episode 4 - Terror of the Zygons (4)

UNIT attempt to track down the Zygon ship while Broton prepares to have the Skarasen attack London. Air Date : 20th-Sep-1975  Read More

Season 13 Episode 5 - Planet of Evil (1)

The Doctor and Sarah answer a distress call and find themselves on Zeta Minor, the last planet of the known universe, where a Morestran expedition has gone missing. Air Date : 27th-Sep-1975  Read More

Season 13 Episode 6 - Planet of Evil (2)

The Doctor realises that Zeta Minor lies on the boundary between the universes of matter and anti-matter and something on the planet won't let the Morestrans leave. Air Date : 4th-Oct-1975  Read More

Season 13 Episode 7 - Planet of Evil (3)

The Doctor makes a deal with the Anti-Matter Beast to return all the anti-matter to the planet but Sorenson is determined to continue his research. Air Date : 11th-Oct-1975  Read More

Season 13 Episode 8 - Planet of Evil (4)

The Doctor tries to convince Sorenson to sacrifice himself for the rest of the crew but Salamar's attempt to deal with the situation causes their problems to multiply. Air Date : 18th-Oct-1975  Read More

Season 13 Episode 9 - Pyramids of Mars (1)

The Doctor and Sarah are drawn off course and, instead of UNIT HQ, they arrive on the same site in 1911. Air Date : 25th-Oct-1975  Read More

Season 13 Episode 10 - Pyramids of Mars (2)

The Doctor, Sarah and Laurence try to find a way to sever Sutekh's link to the mummies while poacher Ernie Clements finds the priory surrounded by a forcefield. Air Date : 1st-Nov-1975  Read More

Season 13 Episode 11 - Pyramids of Mars (3)

The Doctor and Sarah try to destroy Sutekh's rocket but the Osiran's mental powers prove too great for them. Air Date : 8th-Nov-1975  Read More

Season 13 Episode 12 - Pyramids of Mars (4)

Sutekh forces the Doctor to transport Scarman and a mummy to Mars, where the Doctor and Sarah try to stop them destroying the Eye of Horus. Air Date : 15th-Nov-1975  Read More

Season 13 Episode 13 - The Android Invasion (1)

The Doctor and Sarah return to Earth in the present day to find a strangely deserted village and woods stalked by white-clad figures. Air Date : 22nd-Nov-1975  Read More

Season 13 Episode 14 - The Android Invasion (2)

The Doctor suspects Crayford brought something to Earth in his rocket, as he and Sarah find themselves hunted by UNIT. Air Date : 29th-Nov-1975  Read More

Season 13 Episode 15 - The Android Invasion (3)

The Doctor is captured by Styggron and left to die in the destruction of the fake village but Sarah escapes from the disorientation chamber to try and rescue him. Air Date : 6th-Dec-1975  Read More

Season 13 Episode 16 - The Android Invasion (4)

The Doctor and Sarah reach Earth and try to warn the research centre about the Kraal invasion before Styggron unleashes his virus. Air Date : 13th-Dec-1975  Read More

Season 13 Episode 17 - The Brain of Morbius (1)

The storm-lashed planet Karn. Near a graveyard of crashed starships, the demented surgeon Solon hides in his castle, the last acolyte of the Time Lord despot Morbius. He only needs one final item to make his master live again... and then the Doctor and Sarah arrive... Air Date : 3rd-Jan-1976  Read More

Season 13 Episode 18 - The Brain of Morbius (2)

The Doctor is captured by the Sisterhood, and Sarah Jane is blinded freeing him. The Doctor has no choice but to go back for a cure, unaware that he is leaving Sarah Jane in the hands of a treacherous Dr. Solon and the renegade Time Lord Morbius. Air Date : 10th-Jan-1976  Read More

Season 13 Episode 19 - The Brain of Morbius (3)

While the Doctor goes to confront the Sisterhood to seek a cure for Sarah Jane's blindness, Solon realizes that he must transfer Morbius' brain into a new body before it is too late. Air Date : 17th-Jan-1976  Read More

Season 13 Episode 20 - The Brain of Morbius (4)

Morbius lives once more, but as a rampaging beast. The Doctor is forced to ally with Dr. Solon to bring him to heel, but the two disagree about what should happen to Morbius. Air Date : 24th-Jan-1976  Read More

Season 13 Episode 21 - The Seeds of Doom (1)

The Antarctic, the near future. A strange seed-pod is unearthed from 20-thousand-year-old ice. The Doctor and Sarah go to investigate, but are too late to prevent the pod infecting a scientist and unleashing a threat to all animal life on Earth... Air Date : 31st-Jan-1976  Read More

Season 13 Episode 22 - The Seeds of Doom (2)

Two employees of the millionaire Harrison Chase arrive at the Antarctic base, and they will stop at nothing to get hold of the second seed-pod. Air Date : 7th-Feb-1976  Read More

Season 13 Episode 23 - The Seeds of Doom (3)

The Doctor and Sarah Jane return to England after their Antarctic ordeal and Chase tries to eliminate them, but they escape and track him down at his estate, where he is preparing to open the Krynoid pod. Air Date : 14th-Feb-1976  Read More

Season 13 Episode 24 - The Seeds of Doom (4)

The Doctor is captured by Chase, who plans to breed the stolen Krynoid pod. He is placed in an automated compost hopper and only Sarah Jane can save him... but will she make it before the Krynoid grows to fruition ? Air Date : 21st-Feb-1976  Read More

Season 13 Episode 25 - The Seeds of Doom (5)

The Krynoid grows to a monstrous size and traps the Doctor and the others in a cottage. The creature demands they turn over the Doctor, while Chase seeks to make an alliance with the alien vegetation. Air Date : 28th-Feb-1976  Read More

Season 13 Episode 26 - The Seeds of Doom (6)

The Doctor, Sarah Jane, and Scorby are trapped in the manor as a possessed Chase stalks them from within, while the gigantic Krynoid prepares to crush them from without. Worse, the alien plant is ready to germinate, spreading its seeds across England. Air Date : 6th-Mar-1976  Read More