Season 20

6E - Arc of Infinity (4 episodes)
A creature from the anti-matter universe attempts physical bonding with the
Doctor, causing the High Council of the Time Lords to execute him to
prevent the full bonding and cataclysm for billions.

6D - Snakedance (4 episodes)
The Mara is still asleep in Tegan's mind and awakes, taking the TARDIS to
Manussa, the world where it was created in the hopes of making itself
reoccur during the 500th Anniversary of its destruction.

6F - Mawdryn Undead (4 episodes)
Enormous coincidences are engineered by the Black Guardian who makes a deal
with an exiled alien boy to have the Doctor destroyed and humiliated by
forcing him to use his remaining regenerations to help a pitiful group of
Mutants.

6G - Terminus (4 episodes)
Turlough, at the Black Guardian's behest, nearly causes the TARDIS to break
up, but instead it locks on to a spacecraft full of space lepers en route
for a delapadated space station where a cure is supposedly given, but the
position of the station may be more important than its function...

6H - Enlightenment (4 episodes)
The Eternals race in sea ships in space for a prize of Enlightenment, which
will enable these creatures with vast powers already to know everything
conceived in time from beginning to end.

6J - The King's Demons (2 episodes)
The Master seeks to usurp history by using an impostor android of King John
to rob the world of Magna Carta.

6K - The Five Doctors (1 episodes)
A Time Lord traitor uses a Time Scoop to gather all of the Doctor's
regenerations and many old foes and friends and places them in the Death
Zone on Gallifrey to deal with the Zone's boobytraps for him and allow him
access to Rassilon himself and the secret of Immortality.

Season 21

6L - Warriors of the Deep (4 episodes)
A Sea Base in a 21st century Cold War is the scene of the Silurians and Sea
Devils renewed attempts to drive the world into war and eliminate the
world's human population.

6M - The Awakening (2 episodes)
The Doctor takes Tegan to visit her grandfather in a quiet English village
where a vast creature with tremendous psychic powers is being awakened by a
reenactment of the English Civil War.

6N - Frontios (4 episodes)
The TARDIS drifts into the far future and is dragged down by what seems to
be mere gravity to the war-torn colony of Frontios where corpses
disappear... as though the planet buries its own dead.

6P - Resurrection of the Daleks (2 episodes)
The Daleks attack and rescue Davros from his cryogenic prison in the hopes
he will find for them a cure to a disease that is destroying them and lure
the Doctor to the station via human duplicates and a time corridor.

6Q - Planet of Fire (4 episodes)
An alien beacon causes Kamelion to take control of the TARDIS and take the
Doctor, Turlough, and an American girl named Peri to the volcanic world of
Sarn where the Master seeks a volcanic gas to repair a terrible injury.

6R - The Caves of Androzani (4 episodes)
The Doctor and Peri become victims of a poisonous substance in the middle
of a war between a mad scientist and his androids, gun runners, a colonial
army, and a corrupt businessman who will stop at nothing, not even the
Doctor's life, to possess total control over the life-prolonging drug
called spectrox...

6S - The Twin Dilemma (4 episodes)
After half killing Peri, the newly regenerated and somwhat unstable sixth
Doctor, decides to become a hermit, but he then encounters an old friend
Azmael and the mathematically gifted Sylvest twins are needed pawns in the
gastropod Mestor's plans for universal domination.

Season 22

6T - Attack of the Cybermen (2 episodes)
The Cybermen have captured a time vessel and then do the same with the
Doctor's TARDIS in their plans to change history and prevent Mondas from
ever being destroyed.

6V - Vengeance on Varos (2 episodes)
The TARDIS' need for the mineral Zyton-7 brings the Doctor and Peri to the
former penal colony of Varos, where prisoners are tortured in a Punishment
Dome and the population is forced to watch while slumped over video screens
in their very homes.

6X - The Mark of the Rani (2 episodes)
A renegade Time Lady's activities in 19th century Earth draw attention from
the Master, and he in turn draws the Doctor when he sets plans in motion
for usurption of history by disrupting the Industrial Revolution.

6W - The Two Doctors (3 episodes)
Dangerous experiments in time travel gain attention on Gallifrey, who
unwittingly send the Second Doctor and Jamie into a trap aided by the
Sontarans designed to isolate a Time Lord's link to his time machine.

6Y - Timelash (2 episodes)
The dictator and mutant Borad plans war with his neighboring planet to rid
himself of his own planet's population, many members of which have already
been exiled down a time corridor called the Timelash.

6Z - Revelation of the Daleks (2 episodes)
Davros has wormed his way into the society on Necros, using its
specialisation in suspended animation and funerals as a front for his
reconstruction of a new Dalek army.

Season 23

7A - The Mysterious Planet (4 episodes)
The Doctor is drawn to a space station and placed on trial by the Time
Lords on charges of interference in the affairs of other planets, and the
first evidence presented by the prosecuting Valeyard is the Doctor and
Peri's visit to Ravolox, a world with a society divided between underground
servants of an immortal robot and a free tribe on the surface, a balance
upset by a fault in the robot's power system and by the arrival of a con
man named Glitz who has come for certain "secrets" left behind in the
tunnels.

7B - Mindwarp (4 episodes)
The second segment of evidence shows the Doctor to appear to turn evil as
we see him actually aid Sil and the Mentors efforts to find new head for
the brain of their ruler, including Peri's...

7C1 - Terror of the Vervoids (4 episodes)
The Doctor presents evidence in his own defense, telling the tale of his
future involvement in murders aboard a spaceliner bound for Earth that
conceal or attempt to conceal an immoral science development.

7C2 - The Ultimate Foe (2 episodes)
The Master disrupts the Trial with the news that the whole thing is a
set-up to disguise crimes of the High Council, and that the Valeyard is
really a near-last regenerative form of the Doctor himself, who takes
refuge in the Matrix, drawing the Doctor and the Master into his deadly
fantasy virtual reality inside...

Season 24

7D - Time and the Rani (4 episodes)
The Rani shoots down the TARDIS, causing injury to the Doctor and his sixth
regeneration, in part of her plan to explode a Strange Matter asteroid
above the surface of the indolent Lakertya.

7E - Paradise Towers (4 episodes)
The Doctor takes Melanie to visit the famed Paradise Towers, to find it
decayed into an urban nightmare whose inhabitants' facades blind them to a
threat to them all from beneath their feet.

7F - Delta and the Bannermen (3 episodes)
The Doctor and Melanie win a trip to 1959 Earth, Disneyland to be precise
but a collision with an American satellite knocks it off course to Wales
and a rock and roll holiday camp to where a certain passenger is tracked by
the genocidal-minded Gavrok and his Bannermen.

7G - Dragonfire (3 episodes)
The villainous Kane who rules Iceworld needs a Dragon's Treasure to obtain
his freedom, so he tricks Glitz and the Doctor into hunting it in the
caverns below the colony.

Season 25

7H - Remembrance of the Daleks (4 episodes)
The Doctor returns to London, 1963, scene of "An Unearthly Child" where we
learn he left something very powerful behind, something that two factions
of Daleks now battle in the streets of London for control of, since it will
give the victor the power of the Time Lords.

7L - The Happiness Patrol (3 episodes)
The Earth colony of Terra Alpha is governed by Helen A who demands that all
her subjects be happy at all times, on pain of death, or at least on pain
of routine disappearance...

7K - Silver Nemesis (3 episodes)
A 17th-century Lady, a group of Nazi Germans, and the Cybermen all battle
each other and the Doctor for possession and control of the three segments
of a statue of living metal called Nemesis, with one purpose in mind,
destruction.

7J - Greatest Show in the Galaxy (4 episodes)
An advertising satellite lures the Doctor and Ace to a Festival at the
Psychic Circus on the planet Segonax, where contestants in the Ring are
subject to death if they fail to entertain the three-person audience.

Season 26

7N - Battlefield (4 episodes)
A UNIT convoy is disrupted when soldiers from another dimension cross to
ours to renew their centuries-old conflict for control of the sword
Excalibur.

7Q - Ghost Light (3 episodes)
A Victorian house in Perivale that haunts Ace's past is indeed haunted in
the past by an alien Survey of life on Earth that has gotten out of
Control, until Light comes again...

7M - The Curse of Fenric (4 episodes)
A plan by Russian commandos to steal a top-secret codebreaking computer
from the British navy in World War II is complicated by an ancient Viking
curse of the area that has manipulated family destinies all through Time,
including Ace's...

7P - Survival (3 episodes)
Peaceful Perivale is not so peaceful after all when the Master uses
kidnappings and cats as a means to lure the Doctor to the dying world of
the Cheetah People where he is trapped, at first in hopes of escape, but
then simply so that he can destroy the Doctor utterly like the animal he is
becoming...

Season 27

8A - Enemy Within (1 episodes)
While en route to take the Master's remains back to Gallifrey, the remains
escape and crash the TARDIS in San Francisco at the end of 1999. There, the
Doctor is accidentally killed, and following his regeneration, he must
recover his memory in time to stop the Master from opening the TARDIS' Eye
of Harmony...