With Nyssa from Traken unexpectedly rejoining the group, Adric aids the Monitor of Logopolis in trying to save the Doctor before time runs out. The Master, at liberty to prepare, is finally ready to reveal his true target, which unknowingly sets off the biggest catastrophe of all time.

With the universe collapsing, the Doctor forms an uneasy alliance with the Master to save it. In case all does not go well, the Watcher takes the Doctor's companions to a safe place, but his plans for them don't stop there. The one hope for all lies back on Earth.

Southern England, 1981. The universe has been saved, but at the cost of the fourth Doctor's life. The newly-regenerated fifth Doctor must rely on his friends to survive as the regeneration threatens to fail…

The TARDIS is plunging toward destruction. But even if the Doctor can escape, is yet another trap waiting?

The Doctor's TARDIS is stolen, and tracking it down reveals the existence of an alien named Kalid controlling events in the past. While the Doctor challenges Kalid's motives for being there, Tegan and Nyssa discover the source of Kalid's power - an even greater threat for the Doctor.

From within their sarcophagus, the gestalt Xeraphin are communicating through Nyssa. But their psychic energy is so powerful it may destroy her body completely.

The Master's TARDIS is repaired and the Doctor must follow him back to 20th century Heathrow, once he has rescued all the passengers and crew from both Concordes.

England, 1215. With the historic signing of the Magna Carta supposedly only days away, the Doctor is startled to find King John apparently intent on provoking civil war - and seemingly in two places at once...

Lanzarote, 1985. Archaeologist Howard Foster raises a strange metal artefact from the sea floor. But how is it linked to the signal the TARDIS received? Why is Turlough suddenly so worried? And why is Kamelion acting so erratically?

While the Master, victim of his own attempt to improve his TCE weapon, seeks restoration through Sarn's numismaton gas, the truth of Turlough's past comes out at last, though to guarantee the safety of his brother and the Sarn people, Turlough must consider a great personal sacrifice.

Sarn prophesy foretells of an outsider who will come to aid the people. It's a role the Master is more than delighted to fill, which finally presents Timanov, the Sarn religious leader, the unbridled support he's sought in his campaign to cull the faithless from among his people. Turlough's secret past, however, is somehow intricately involved in all this, and the reluctance of its disclosure is enough to threaten all friendly ties with the Doctor.

While the Master, victim of his own attempt to improve his TCE weapon, seeks restoration through Sarn's numismaton gas, the truth of Turlough's past comes out at last, though to guarantee the safety of his brother and the Sarn people, Turlough must consider a great personal sacrifice.

The situation on Androzani Minor is building toward a violent confrontation, and the Doctor and Peri are slowly succumbing to spectrox toxemia.

England, the 1820s. As the Industrial Revolution gathers pace, the village of Killingworth is disturbed by crazed Luddite miners intent on smashing all machinery and engineers. But is there another cause of the situation?

The Master uses The Rani's mind-controlling parasites to keep a meeting of Earth's leading scientists from being cancelled, and helps her plant transformation land mines for The Doctor, as he continues to propose an alliance with her in ruling over Earth.

The Valeyard's true identity is revealed and the trial aborted, but the Doctor and Mel must pursue his new enemy into the Matrix itself, where nothing is quite what is seems…

The final part of this epic adventure. The Doctor and the Valeyard have entered the world of the Matrix. Can the Doctor defeat the evil incarnation of himself ?

Perivale, England, the late 1980s. People are vanishing into thin air under the baleful stare of a very strange cat. The Doctor and Ace learn that, in the battle for survival, success can carry a terrible price...

The Doctor and Paterson manage to escape from the Master and join up with Ace and her friends, where the Doctor tries to find a way to get them all off the planet before it explodes.

Ace manages to transport the Doctor and the others back to Perivale but the Master is also there, preparing for a final showdown with the Doctor.