Attempting to return to UNIT HQ, the Doctor (Tom Baker) and Sarah land in England in 1911, where an ancient force is preparing to return and wreak destruction on the Universe. Sutekh the Destroyer, last of the Osirans, is planning to free himself from his prison on Mars. His robot Mummies are building a rocket to destroy the device which holds him prisoner and If he isn't stopped, there is not a force in the Universe which can stand against him.

Another adventure for the intrepid time traveller. The Doctor (Tom Baker) and Romana (Lalla Ward) are holidaying in Paris when they stumble across the mysterious Count Scarlioni (Julian Glover) to steal the Mona Lisa. With the aid of inept detective Duggan (Tom Chadbon) they discover that the Count already has several Mona Lisas walled up in his cellar - all of them painted by Leonardo Da Vinci - and when the Doctor finds out that Scarlioni is also conducting time experiments he begins to realize that his latest foe is not all that he seems... Due in part to an independent television strike, this story achieved the series' highest ever viewing figures, with the final episode peaking at 16.1 million.

Another adventure for everyone's favourite Time Lord. The Doctor (Tom Baker), Sarah and Harry land on space station Nerva, where the chosen few of the human race are in suspended animation, awaiting the call to revive. However, an insectoid alien life form known as the Wirrn has infiltrated the Ark and cut through the humans' alarm clock. The Wirrn now intend to use the sleepers as the hosts for their hatchings and claim the Earth as their own.

The Third Doctor (Jon Pertwee) faces terrifying plastic Autons and the evil Master in these two classic Doctor Who adventures. In 'Spearhead from Space' (1969), the newly-regenerated Doctor begins his exile on 20th century Earth after being forbidden to continue his travels through time and space by his fellow Time Lords. His arrival coincides with a shower of strange meteorites, which are promptly investigated by the United Nations Intelligence Taskforce. Although his old friend Brigadier Alastair Gordon Lethbridge-Stewart (Nicholas Courtney) is initially suspicious of the Doctor's new appearance and personality, he is forced to ask for his help when several of the meteorites go missing. The Doctor discovers that the meteor shower was in fact the first wave of an invasion by hostile alien intelligence the Nestene; phase two begins when the Autons - deadly plastic mannequins created by the Nestene agents on Earth - launch an attack on the unsuspecting public. In 'Terror of the Autons' (1970), the Doctor must pit his wits against the Nestene invaders, now teamed with renegade Time Lord the Master. This episode marks the first appearance of Jo Grant (Katy Manning), Captain Mike Yates (Richard Franklin) and The Master (Roger Delgado).

Another adventure for the intrepid space/time traveller. The Doctor (Tom Baker) has returned the TARDIS to his home planet of Gallifrey, but why has he forbidden Leela (Louise Jameson) to accompany him? Why, upon claiming the Presidency, does he expel every senior Time Lord to the outer wastes? And what plan is he hatching with the hostile Vardans? The only people he seems to have taken into his confidence are K9 and Chancellor Borusa, but whatever game the Doctor is playing, he has reckoned without the return of an old foe... This story marks the departure from the series of Leela and K9 Mark 1.

The newly regenerated Doctor (Tom Baker), assisted by Sarah, Harry and the Brigadier, has to track down the theft of the components for a powerful new laser gun, and the death of a prominent politician. Sarah investigates the mysterious Think Tank, where it becomes clear that robot K-1 is being misused by its political extremist masters and the Doctor has to prevent the robot from being used to start an atomic war. Tom Baker's first story as the Doctor.

The TARDIS materialises in an English quarry where Sarah is involved in a rock fall. When she is rescued, she is clutching a stone hand, which takes control of her and forces her to take it into the core of a nuclear reactor. The Doctor (Tom Baker) arrives too late to stop the hand from regenerating into an alien lifeform known as Eldrad, who demands to be returned to her home planet of Kastria. The Doctor obliges, but all is not as it seems with Eldrad. This was Sarh Jane Smith's last adventure with the Doctor, although she later returned in 'K-9 and Company', 'The Five Doctors' and 'Downtime'.

Jon Pertwee stars as the time travelling Doctor, who once more finds the planet under threat. Trying to avert a war which will bring Earth under the domination of the Daleks and their ferocious slaves (the Ogrons), the Doctor fights one of the biggest challenges he has faced so far.

The Doctor (Patrick Troughton), Jamie and Zoe are captured and witness a series of war games staged by aliens on a mysterious planet, with warriors from history pitted against each other. They discover this to be a plot by the War Lords, who are being aided and abetted by the War Chief, a member of the Doctor's own race. In desperation the Doctor summons his people, the Time Lords, for help. This was Patrick Troughton's last regular appearance as the Doctor, and is the first story to feature the Time Lords.

The Doctor (Tom Baker) and the newly-regenerated Romana land on a strangely familiar planet and investigate the drilling that is going on there. The Daleks are searching for their creator, Davros (last seen in 'Genesis of the Daleks'), in the hope that he can assist them in their war with the Movellans. The Doctor has to reach the evil Kaled scientist before the Daleks, but just who can he trust?

Another adventure for everyone's favourite Time Lord. A may-day call to the Doctor (Tom Baker) and Sarah takes them to the outermost horizons of the Universe where they find a Morestran military expedition stranded on a remote planet. The Doctor has to battle an anti-matter monster, the unstable Morestran Commander Salamar, and scientist Professor Sorenson, who is transforming into a deadly Anti-man.

Another adventure for the third incarnation of the famous timelord. The action this time takes place on Earth, with the Doctor (Jon Pertwee) coming up against all kinds of opposition within the British space program when he attempts to investigate some mysterious messages travelling to and from the returning spaceship Mars Probe 7. When the ship's astronauts arrive back home, suspicious circumstances prevent the Doctor from speaking to them, which only makes him more determined to get to the bottom of the matter.

The Doctor (Tom Baker) and Sarah Jane return for a visit to Earth, only to discover that a wave of evil Mandragora energy has hitched a ride on the TARDIS and is now being used to plunge mankind back into the dark age. They have to thwart not only the murderous count, but also prevent the mad monk Heironymous and the Cult of Demnos from unleashing the Mandragora Helix on mankind.

The Doctor (Tom Baker) and Sarah (Elisabeth Sladen) arrive on storm ridden planet Karn, where mad scientist Dr Solon (Philip Madoc) is creating a hybrid monster body for the brain of renegade Time Lord Morbius (voice of Michael Spice). Also on the planet are the Sisterhood of the Flame, who believe that the Doctor has been sent by the Time Lords to steal their Elixir of life. The Doctor must convince the Sisters of his good intentions and prevent Solon from returning Morbius to life.

Two episodes from the Tom Baker era 'Doctor Who', devoted to the Doctor's favourite metallic pooch - K9. In 'The Invisible Enemy', a mysterious cloud is causing havoc in space, infecting all those who pass through it with an intelligent virus which could spread throughout the whole galaxy. The Doctor (Baker) and Leela (Louise Jameson) try to come to the rescue, but the TARDIS passes through the cloud itself, leaving the Doctor infected with the virus. He and Leela then try to find help at a nearby medical station, where they meet the eccentric Professor Marius and his pet robot K-9. In 'K9 and Company', the pilot from the 'Doctor Who' spin-off series, the Doctor's former companion, Sarah-Jane Smith (Elisabeth Sladen), arrives to take up residence with her Aunt Lavinia at the village of Moreton. She finds the house deserted apart from a crate marked for her attention, which turns out to contain a gift from the Time Lord: K9 Mark 3. The mechanical dog teams up with Sarah to investigate Aunt Lavinia's disappearance, and together they unearth evidence of witchcraft.

The Doctor is on a mission, travelling back to the middle ages to locate some missing scientists. He is, however, seriously inconvenienced when he meets a Sontaran warrior. Jon Pertwee stars.

The entire second season of the 1970s BBC sci-fi series. 'Redemption' sees Orac's prediction of the Liberator's destruction looking likely to be fulfilled when the ship's original owners arrive and take the rebels prisoner. In 'Shadow', Blake becomes involved with an interplanetary crime syndicate. 'Weapon' sees Blake and crew set out to steal a deadly 'delayed-effect' gun, which Servalan also wishes to possess. In 'Horizon', the Liberator heads for the edge of the Galaxy, only to be taken prisoner on the planet Horizon. 'Pressure Point' sees Blake attempting to destroy the Federation's control centre, only to walk into a trap set by Travis. In 'Trial', Travis is made a scapegoat by Servalan for their failure to capture Blake. 'Killer' sees Blake and his crew stumbling upon a derelict spaceship whilst on a mission to crack the Federation's new transmission code. The craft houses a deadly plague which could threaten the existence of the entire universe. In 'Hostage', Travis tries to trap Blake by kidnapping his cousin, Inga. 'Countdown' sees Blake and crew coming to the aid of the planet Albian, whose population are dying from radiation poisoning. In 'Voice from the Past', a telepathic signal forces Blake to reroute the Liberator to an asteroid where Travis lies in wait. Whilst 'Gambit' sees Blake, Cally and Jenna visit a gambling world to find the man who knows the location of the Federation's Star One. Avon and Villa, meanwhile, choose to take Orac on an illicit gambling spree. In 'The Keeper', Blake tries to obtain the key to Star One from a tribal chief on the planet Goth. However, Travis has beaten him to it. Finally, 'Star One' sees Blake at last launch his attack on the Federation's headquarters, unaware that an alien fleet is poised to invade.