All the stories in this season were interconnected, several forming a loose story arc relating to Space Station Nerva. The Cybermen returned to the series for the first time since The Invasion. Genesis of the Daleks, a story which introduced Davros and showed the creation of the Daleks, is one of the most famous of all Doctor Who serials.
Episode 1
Robot (1)
Dec 28, 1974
The Doctor changes form again. Before he has fully re-covered, something of colossal strength steals a secret weapon, and the convalescent Doctor starts to investigate.
Episode 2
Robot (2)
Jan 4, 1975
The Doctor and Sarah Jane become convinced Think Tank are behind the electronic component thefts but are unable to stop them carrying out another raid.
Episode 3
Robot (3)
Jan 11, 1975
Sarah Jane and Kettlewell infiltrate an SRS meeting to try and find out what Miss Winters is up to but there is a surprise in store.
Episode 4
Robot (4)
Jan 18, 1975
UNIT attempt to get into the bunker to stop Miss Winters setting off the world's nuclear missiles but first they have to get past the K1.
Episode 5
The Ark in Space (1)
Jan 25, 1975
The Doctor's attempt to give Harry a trip in the TARDIS sees the two of them and Sarah Jane arriving onboard a space station in the far future, with some rather deadly security mechanisms.
Episode 6
The Ark in Space (2)
Feb 1, 1975
The Doctor and Harry revive the Ark's medtech, Vira, to help Sarah Jane. But when station commander Noah is revived, he becomes suspicious of the newcomers.
Episode 7
The Ark in Space (3)
Feb 8, 1975
Knowing that Noah has been infected by the Wirrn, the Doctor persuades Vira to halt the reviving of her people, knowing it will place them in danger as well.
Episode 8
The Ark in Space (4)
Feb 15, 1975
The Doctor tries to protect the humans still in cryogenic suspension from the Wirrn, who are determined to use Earth as their new breeding ground.
Episode 9
The Sontaran Experiment (1)
Feb 22, 1975
The Doctor, Sarah Jane and Harry teleport to Earth to ensure the planet is safe for the survivors on board Nerva Beacon to return and reinhabit their world. A Sontaran named Styre has captured a group of humans and is conducting experiments on them to discover the human body's weaknesses, as part of the Sontaran's goal for domination of the galaxy.
Episode 10
The Sontaran Experiment (2)
Mar 1, 1975
The Doctor learns that Styre has been experimenting on the Galsec crewmembers to pave the way for a Sontaran invasion of Earth and decides the only way to halt his plans is to challenge him to a duel.
Episode 11
Genesis of the Daleks (1)
Mar 8, 1975
The planet Skaro, the distant past. The Time Lords divert the Doctor, Sarah Jane and Harry to this war-torn world, and give the Doctor a mission: the evil of the Daleks is about to be born here, and the Doctor is to try to ensure they evolve into less lethally aggressive beings - or, failing that, to avert their creation altogether. But has even the Doctor the right to commit genocide?
Episode 12
Genesis of the Daleks (2)
Mar 15, 1975
The Doctor and Harry are taken to the Kaled bunker where Davros is preparing to demonstrate the Daleks, while Sarah Jane is captured by the Thals and taken to their city as a slave worker.
Episode 13
Genesis of the Daleks (3)
Mar 22, 1975
The Doctor and Harry head to the Kaled city to alert the authorities to Davros' plans while Sarah Jane and Sevrin are forced to work on the completion of the Thals' rocket.
Episode 14
Genesis of the Daleks (4)
Mar 29, 1975
The Doctor fails to prevent the Thals from destroying the Kaled city but they don't have long to enjoy their victory before the Daleks attack.
Episode 15
Genesis of the Daleks (5)
Apr 5, 1975
The Doctor is forced to give Davros full details of future Dalek victories but opposition to Davros' plans is growing among the Kaleds and soon there is open rebellion.
Episode 16
Genesis of the Daleks (6)
Apr 12, 1975
Gharman tries to convince the Kaleds to vote against the Dalek project but Davros has a trick up his sleeve, while the Doctor works to destroy the tape recording of Dalek victory and the Thals plan an intervention of their own.
Episode 17
Revenge of the Cybermen (1)
Apr 19, 1975
The orbit of Jupiter, the 25th century. Arriving back on the Nerva Beacon much earlier in history, the Doctor and his friends discover the satellite beset by space plague while its crew struggles to keep space traffic away from Voga, the newest moon of Jupiter. But what is the connection between Voga, the plague, and some old enemies of the Doctor?
Episode 18
Revenge of the Cybermen (2)
Apr 26, 1975
The Doctor transmits Sarah Jane and Harry down to Voga to cure Sarah Jane of the Cybermat's poison but Kellman's sabotage means he is unable to bring them back.
Episode 19
Revenge of the Cybermen (3)
May 3, 1975
The Cybermen force the Doctor, Stevenson and Lester to carry bombs to the centre of Voga while Sarah Jane, Harry and Tyrum decide to contact Vorus.
Episode 20
Revenge of the Cybermen (4)
May 10, 1975
The Doctor, Harry and Lester try to destroy the Cybermen's relay device, while the Vogans prepare to destroy Nerva even though Sarah Jane is still on board.