The TARDIS takes the newly regenerated Doctor to Earth to begin his exile. Brigadier Lethbridge-Stewart leads a UNIT investigation into a mysterious meteorite shower.

A recovered Doctor escapes the hospital and joins UNIT in their investigation. Meanwhile, Channing directs one of his Auton servants to recover a meteorite.

Sam Seeley has found one of the meteorites but the Autons want it back and are closing in. General Scobie visits Auto Plastics, playing into the hands of Channing.

The invasion begins as Auton shop dummies come to life and attack the public. The Doctor and UNIT infiltrate Auto Plastics where the Doctor faces the Nestene consciousness.

UNIT are summoned to Wenley Moor research station which is experiencing mysterious power losses. In the nearby caves, one of the staff has been killed and another sent insane.

Investigating the caves, the Doctor is attacked by a dinosaur-like creature. Dr Quinn is hiding a secret that could endanger the lives of everyone.

The creature from the caves, wounded and dangerous, is on the loose on Wenley Moor. Dr Quinn attempts to recover it and is unwilling to listen to the Doctor’s warnings.

Fearful of a war breaking out between the Silurians and mankind, the Doctor attempts to make peace between the races. But there are those on both sides unwilling to listen.

When the Silurian leader is killed, all hopes of peace are lost. The Silurian’s infect Major Baker with a virus deadly to humans and release him to spread the infection.

As the Silurian plague quickly spreads, the Doctor desperately searches for a cure. But the Silurians are aware of the Doctor’s efforts and intend to stop him.

With the antidote to the plague found, the Silurians retaliate and take over the research centre. They now intend to destroy the Van Allen Belt, resulting in death for all mankind.

Contact has been lost with Mars Probe 7. When contact is also lost with the recovery ship, UNIT is called in and the Doctor learns that someone is sending messages to the vessel.

Recovery 7 has returned to Earth but the UNIT convoy transporting the capsule is ambushed. The Doctor is able to relocate the capsule, but is he too late?

The recovery capsule is empty with the astronauts seemingly kidnapped. But Liz notices that the radiation count is high and the Doctor deduces that the occupants were not human.

Liz has been captured by Reegan who is holding the three aliens captive. The Doctor suspects Quinlan’s part in the conspiracy, but Quinlan is killed before he can reveal the truth.

The Doctor prepares to pilot the Recovery 7 ship into space, but Reegan sabotages the fuel supply which will send the Doctor into the sun.

On board a vast spacecraft, the Doctor meets the alien captain who demands the return of the three ambassadors sent to Earth or he will destroy the world.

General Carrington is behind the kidnapping of the ambassadors and intends to turn the world against the aliens by revealing their true identity to the world in a TV broadcast.

UNIT are at a project run by Professor Stahlman who intends to penetrate Earth’s crust. But the drilling has already released something deadly from beneath the Earth’s surface.

The green slime oozing from the drill head is transforming men into monsters. Stahlman refuses to listen to the warnings and resorts to sabotage so that his project may continue.

Transported to a parallel world, the Doctor discovers that England is under military rule and the drilling project is at a more advanced stage.

In the parallel world, the drilling project is about to penetrate the Earth’s crust. The Doctor, arrested as a spy, is unable to convince his captors of the danger that faces them.

In the parallel world, Earth’s crust has been penetrated, releasing terrible forces from within the Earth. The Doctor must escape back to his world to prevent the same catastrophe.

As the Earth in the parallel world faces destruction, the Doctor is desperate to return to his world to warn them of the danger. But time is running out.

The Doctor has escaped the doomed, parallel Earth and has returned to his own world where he attempts to put a halt to the drilling project.

The Master, a renegade Time Lord and a rival of the Doctor’s, arrives on Earth and paves the way for an invasion by the insidious Nestene Consciousness.

The Doctor follows the Master’s trail to the circus. Meanwhile, the Master has used his hypnotic powers to take control of a plastics factory where he creates the deadly Autons.

The Doctor and the Brigadier trace the Master to the plastics factory but they are too late. The only clue to the Master’s plans is a single plastic daffodil.

The Doctor and UNIT race to prevent the Master from broadcasting the deadly activation signal and opening the channel for the Nestene’s arrival on Earth.

At Stangmoor Prison, the Doctor and Jo watch a demonstration of the Keller Machine which can extract evil impulses from criminals. But the experiment goes wrong and a man dies.

A full scale riot takes place at the Prison and Jo is taken hostage. Meanwhile, at the World Peace conference, the Chinese delegate’s aid prepares to kill the American delegate.

The Master is behind the Keller Machine and uses it to recruit the rioting inmates at Stangmoor Prison. He plans to capture a missile and fire it at the World Peace Conference.

The mind parasite within the Keller Machine becomes too powerful for the Master to control. It learns how to move of its own accord and goes on the hunt for new minds.

The Master forms an uneasy alliance with the Doctor so that between them they can subdue the Keller Machine which is now out of control.

The Keller Machine breaks free of the Doctor’s restraining device and the Doctor has no choice but to turn the parasite against the Master.

Axos lands on Earth. The Axons ask only to be allowed to repair their damaged ship and offer the gift of the miraculous Axonite in return. But the Axons aren’t all that they seem.

The Master is in league with the Axons who intend to consume the Earth. The Doctor subjects Axonite to tests and discovers the terrible truth.

The Axons reveal their true nature and attempt to obtain the secret of time travel. Meanwhile, the Master, forced to work for UNIT, concocts a plan to strike back at Axos.

With Axos poised to destroy the world, the Doctor appears to switch sides and allies himself with the Master. Together they plan to escape the Earth, leaving it to Axos.

The TARDIS takes the Doctor and Jo to a barren world in the far future where human colonists are scratching a living. But at night, the colonists are menaced by a monster.

The Interplanetary Mining Corporation, represented by Captain Dent, arrives on the planet claiming that the colonists have no right to be there.

When Jo attempts to break into the IMC ship to find incriminating information, she is captured and held hostage. If the Doctor doesn’t cooperate, Captain Dent will have Jo killed.

The Master arrives, posing as an adjudicator from Earth who has come to settle the dispute between the colonists and the miners. However, the Master has an agenda of his own.

With Jo held prisoner in his TARDIS, the Master forces the Doctor to take him to the underground city of the primitives. Any sign of treachery from the Doctor and Jo will die.

In the underground city, the Doctor and the Master confront the guardian of the doomsday weapon. The miners make their last move to force the colonists to leave the planet.

The Doctor tries to prevent Professor Horner from breaking into an ancient barrow near the village of Devil’s End. Posing as the village vicar, the Master summons dark forces.

Devil’s End is sealed off from the outside world by a heat barrier. The Doctor and Jo return to the barrow where they are confronted by the gargoyle, Bok.

The Doctor attempts to help the Brigadier penetrate the heat barrier but is attacked by the Master’s servant in a helicopter. The Master prepares to summon the Daemon Azal.

The Doctor is captured by the villagers who are under the Master’s control. Jo goes to the church to prevent the Master from summoning Azal for the final time, but is too late.

UNIT have penetrated the heat barrier and launch an attack on the gargoyle, Bok. In the cavern, the Daemon Azal confronts the Doctor and the Master to decide the fate of mankind.

Sir Reginald Styles, a diplomat with the best chance of averting a war between Russia and China, is almost killed by a mysterious guerrilla.The fighter then disappears with Jo and the Doctor - into a terrifying future Earth ruled by Daleks.

A captive of the guerrillas, the Doctor discovers they intend to change history. Jo is transported to the 22nd Century where she unwittingly gives vital information to the Daleks.

The Doctor arrives in a bleak future where Earth is ruled by the Daleks and mankind is enslaved. Rescuing Jo, the two escape but the brutish Ogrons are in pursuit.

The Controller betrays the Daleks and is exterminated. The Daleks travel back in time to the 20th Century to ensure that the peace conference fails.

The planet Peladon is hoping to join the Galactic Federation. But King Peladon’s Chancellor has been murdered and it seems that the legendary royal beast, Aggedor is to blame.

The work of the committee is hampered by sabotage, fear and suspicion. The Doctor knows the Ice Warriors of old and believes that they may be the guilty party.

The Doctor is sentenced to a fight to the death in the pit with the King's champion, Grun. But the saboteur and killer is still at large.

Hepesh, supported by the delegate from Arcturus, is revealed to be behind the attacks. Arcturus is killed but Hepesh escapes to rouse a rebellion against the King.

The Doctor and Jo visit the Master who is held prisoner on an island. There they learn that several ships have recently been sunk in the area and the Doctor decides to investigate.

The Doctor is eager to make peace between the Sea Devils and the humans but has discovered that the Master is up to his old tricks.

Jo attempts to rescue the Doctor who is being held prisoner by the Master and Trenchard. The Master plans to summon the Sea Devils from beneath the waves.

The Doctor attempts to persuade Captain Hart of the danger that the Master represents. Eager to make contact with the Sea Devils, the Doctor journey’s to the sea bed.

The Doctor is captured by the Sea Devils and taken to their undersea base. There he tries to make peace with the creatures, but his efforts are thwarted by the Navy.

The Sea Devils come to the surface and attack the Naval base. The Doctor is forced to create a machine that will awaken the creatures across the entire world.

The Time Lords send the Doctor to a Skybase above the planet Solos in the 30th Century. The Marshal of the Skybase is determined to prevent Solos achieving independence from Earth.

Fearing Jo has died in Solos's hostile environment, the Doctor is forced to work with the scientist, Jaeger, to make the planet's atmosphere breathable for humans.

Ky opens the message box but cannot understand the ancient carved tablets inside. The Marshal seals the Doctor and his friends in the caves and prepares to gas them to death.

The Doctor deduces the true meaning of the ancient carvings and must brave the intense radiation of the thaesium caves to retrieve a crystal.

With Jo held prisoner, the Doctor is forced to work for the Marshal. The Earth Investigator’s ship prepares to dock at Skybase.

Despite the Doctor's arguments, the Earth Investigator reinstates the Marshal as commander of Skybase. Bombarded by thaesium radiation, Ky begins an incredible transformation.

Masquerading as research scientist, Professor Thascales, the Master is using a device called TOMTIT to summon an ancient and powerful creature from beyond time.

The Doctor tracks the Master down to the Newton Institute. There, after a disastrous attempt to summon Kronos, the Master prepares to use TOMTIT again.

Krasis, High Priest of Atlantis has been summoned by the Master to help him find the crystal of Kronos. The Master uses TOMTIT to summon threats from the past to attack UNIT.

As UNIT approaches, the Master leaves for Atlantis in his TARDIS. However, the Doctor is not far behind.

Arriving in Atlantis, the Master seduces the beautiful Queen Galleia so that he might possess the crystal of Kronos. But it is protected by a guardian who is half man, half beast.

With the crystal of Kronos in his possession, the Master prepares to release the Chronovore. The Doctor is powerless to stop his nemesis as the end of Atlantis approaches.

Attacked by an antimatter creature the Doctor sends an SOS to the Time Lords.

The Doctor and Jo pass through the black hole to the desolate world of antimatter.

The Doctors are trapped in the universe of antimatter where they confront Omega.

Omega intends to escape his antimatter world and needs the Doctors to take his place.

On the SS Bernice the TARDIS is stolen by a giant hand and a dinosaur attacks...

The Doctor and Jo have been miniaturised and are trapped inside a Miniscope peepshow.

The Drashigs are rampaging through the Miniscope in pursuit of Jo and the Doctor.

The Doctor is desperate to save the lives of Jo and everyone trapped inside the Miniscope.

The TARDIS lands inside an Earth spaceship in the far future which is attacked by Ogrons.

The Doctor realises someone is provoking a war between Earth and Draconia.

Accused of being a spy, the Doctor is sentenced to imprisonment on the Moon.

The Doctor and Jo are the Master's prisoners.

The Doctor reveals the plan to provoke war to the Draconians but the Master escapes.

The Doctor leads a mission to the Ogron home world to apprehend the Master and rescue Jo.

Injured by the Orgrons, the Doctor asks the Time Lords to send the TARDIS after the Daleks. Leaving him to sleep and recuperate, Jo goes to explore the planet Spirodon.

The Doctor awakes from his coma, befriends some Thals but is captured by the Daleks.

In the Dalek city, the Doctor breaks out of his prison cell and joins forces with the Thals. With the Daleks in pursuit, he is forced to improvise a daring escape plan.

The Doctor and the Thals escape from the Dalek city and the Doctor is delighted to find Jo is alive. But the Daleks are preparing deadly bacteria to kill all life on the planet.

Desperate to prevent the Daleks from releasing their plague, the Doctor, Jo and the Thals infiltrate their base. But the Daleks detect the intruders!

A force of ten thousand Daleks is coming to life below the surface of Spiridon. The Doctor and the Thals must find a way to defeat the Daleks before they invade the galaxy.

In Wales, a dead miner is found glowing green. UNIT investigates and Jo empathises with the environmentalism of Cliff Jones who is opposing the pollution from Global Chemicals.

Investigating the old mine workings, Jo and miner, Bert, become trapped beneath the surface when the lift is sabotaged. Bert touches some green slime and becomes infected.

The Doctor and Jo discover the mine’s terrible secret. Global Chemicals’ managing director, Stevens is determined that they won’t live to reveal what they have learnt.

The Brigadier attempts to seal the giant maggots in the mine with explosives, but this only results in the creatures burrowing to the surface.

Captain Mike Yates is taken over by the super computer, BOSS and ordered to kill the Doctor. Cliff and Jo are trapped by the maggots as UNIT launch their attack.

In the final episode Jones is struck down with the deadly virus and the Doctor uses the Metebelis crystal to break the computer's hold over Stevens.

UNIT investigates when scientists go missing kidnapped by an alien trapped in the 13th Century. Travelling back in time in the TARDIS, the Doctor is unaware that he has stowaway.

The Doctor discovers that the alien is a Sontaran warrior called Linx who is trying to repair his spaceship. Sarah is convinced that the Doctor is responsible for the abductions.

Linx is providing advanced weaponry to Irongron and his men who prepare to attack Sir Edward’s castle. The Doctor is forced to improvise a defence, but will it be enough?

As the repairs to Linx’s spaceship are completed and he prepares to take off, the Doctor races to save the captured scientists and to prevent the course of history being changed.

The Doctor and Sarah return in the TARDIS to present day London but are mystified when they find the city completely deserted.

The Doctor plans to capture a dinosaur so that he can discover who is transporting them through time. But Mike Yates is in league with the enemy and is ordered to stop the Doctor.

The Doctor has captured a Tyrannosaurus Rex but the conspirators don’t intend for it to remain captive for long. Sarah follows a lead but places herself in the hands of the enemy.

Sarah awakens to discover that she is on a spaceship that left Earth months ago and is heading for a new world. The Doctor is framed for causing the return of the dinosaurs.

Sarah discovers that the spaceship passengers are all victims of a deception, but not all are willing to believe her story.

Dinosaurs are appearing all over London in a last effort to frighten people away as Professor Whitaker prepares to initiated ‘Operation Golden Age’.

The TARDIS suffers a power drain and is forced down on the planet Exxilon. Sarah is captured by the primitive inhabitants and the Doctor comes face to face with his oldest enemies.

The Daleks weaponry is rendered useless by the power drain and they are forced to make a truce with the Doctor and the members of the expedition from Earth.

The Daleks force the Exillons to work as slave labour to mine the life saving parrinium. The Doctor and Bellal brave the puzzles and traps of the Exxilon city.

The Doctor and Bellal arrive at the centre of the Exxilon city but the Daleks are preparing to depart and launch a deadly plague missile that will kill everyone left behind.

The Doctor makes a return visit to Peladon some years after his previous visit. There he discovers that several miners have died and the ghost of Aggedor is to blame.

Chancellor Ortron accuses the Doctor and Sarah of being in league with the rebel miners and sentences them to be punished by Aggedor himself.

Desperate to avoid a revolt from the miners, the Doctor attempts to expose the fraud of Aggedor’s ghost. Alpha Centauri has summoned Federation troops, but whose side are they on?

The Ice Warriors have taken control of Peladon. Pretending to cooperate, the Doctor concocts a plan to defeat the invaders.

Commander Azaxyr and his Ice Warriors are revealed as traitors, in league with Galaxy 5. The Doctor intends to turn Aggedor against Azaxyr, but it may already be too late.

The Doctor and the miners take the upper hand in the fight to reclaim Peladon from the Ice Warriors. But Eckersley is unwilling to give up and takes Queen Thalira hostage.

The Doctor receives a mysterious package from his old companion, Jo Grant. Sarah joins Mike Yates to investigate sinister events at a Buddhist meditation centre.

Lupton, now under the control of a giant spider, infiltrates UNIT HQ and steals the Metebelis crystal. But the Doctor is unwilling to give it up so easily and a chase begins.

Following Lupton, Sarah is transported to Metebelis 3 where she is captured by the human villagers. The Doctor uses the TARDIS to follow Sarah, but the spiders are waiting.

With the Doctor in a coma, his only hope of survival lies with a device inside the TARDIS. Sarah is captured by the spiders and is held prisoner in their larder.

Sarah makes a bargain with the Queen Spider and returns to Earth with the Doctor in the TARDIS. There they meet K’anpo, the Doctor’s Time Lord guru who has the Metebelis crystal.

The Doctor takes the blue crystal and returns to Metebelis 3 where he must face the spider ruler, the Great One. But it is an encounter that he may not survive.