第 21 季 共 24 集
播出时间：1984年1月6日
第 1 集 Warriors of the Deep (1)
播出时间：1984年1月6日
Earth's ocean floor, 2084. With two superpowers poised on the brink of a devastating photonic war, a missile base comes under attack from the reptilian Sea Devils and Silurians, intent on eradicating the upstart human race and reclaiming the planet…
第 2 集 Warriors of the Deep (2)
播出时间：1984年1月7日
Just are the Doctor gains a tentative trust from the humans, a Silurian battle cruiser approaches. The Doctor warns Commander Vorsha to hold his fire and find out what they want, but is the level-headed commander one who'll listen?
第 3 集 Warriors of the Deep (3)
播出时间：1984年1月13日
With Silurians and Sea Devils attacking the air locks, the saboteurs use the distraction to launch plans for disabling vital functions of the base. With all the strife going on around him, and an electricity-generating myrka on the loose, the Doctor endeavors to bring a little sunshine into their unhappy undersea lives.
第 4 集 Warriors of the Deep (4)
播出时间：1984年1月14日
With Silurians in control of the base, Icthar reveals his plan for a final solution to Earth's human problem, which presents the Doctor a great moral dilemma.
第 5 集 The Awakening (1)
播出时间：1984年1月20日
The sleepy English village of Little Hodcombe, 1984. The village re-enactment of the English Civil War is in full swing, but a malign alien presence intends the mock-battles to be rather more realistic than planned...
第 6 集 The Awakening (2)
播出时间：1984年1月21日
The Malus, an alien that's purely evil, needs the civil war re-enactments to become authentic so it can feed off the psychic energy of dying and embattled men and fully revive. Not if the Doctor can derail things, of course.
第 7 集 Frontios (1)
播出时间：1984年1月27日
The planet Frontios, in the distant future. Following Earth's destruction, a tiny colony struggles to eke out a life on this desolate world. But where do the bombardments that threaten them originate from? Little does the Doctor suspect that somewhere nearby lurks a power capable of ripping even the TARDIS apart…
第 8 集 Frontios (2)
播出时间：1984年1月28日
Following the destruction of the TARDIS, the only part of it left is the hat stand. So Turlough uses it as a weapon! Plantagenet gets swallowed by the earth, and Norna and Turlough discover the Tractators.
第 9 集 Frontios (3)
播出时间：1984年2月3日
Trying to rescue the Doctor from the Tractator's trap, Tegan finds herself and the Doctor in even more trouble. Turlough goes a bit mad, and reckons he knows the evil of the Tractators from old.
第 10 集 Frontios (4)
播出时间：1984年2月4日
The Doctor tries to deal with the Tractator's cunning plan, despite Turlough's best intervention. They discover the splintered TARDIS in the tunnels beneath the planet's surface, but how will they put it together again?
第 11 集 Resurrection of the Daleks (1)
播出时间：1984年2月9日
London's Docklands, 1984. Why are uniformed policemen gunning down strangely-dressed vagrants in broad daylight? A prison ship in the far future - who is the sole prisoner aboard the craft? And why are these two locations linked by the time corridor the TARDIS has been sucked into?
第 12 集 Resurrection of the Daleks (2)
播出时间：1984年2月16日
As the surviving station crew work to destroy the space station, Davros consolidates his power and the Daleks launch a fiendish scheme to use the Doctor against the Time Lords.
第 13 集 Planet of Fire (1)
播出时间：1984年2月24日
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?
第 14 集 Planet of Fire (2)
播出时间：1984年2月25日
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.
第 15 集 Planet of Fire (3)
播出时间：1984年3月2日
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.
第 16 集 Planet of Fire (4)
播出时间：1984年3月3日
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.
第 17 集 The Caves of Androzani (1)
播出时间：1984年3月9日
The planet Androzani Minor, the distant future. In the planets' caves war rages between government troops and the android warriors of the mysterious Sharaz Jek. But what makes spectrox, the substance they battle to control, so valuable? And how far will the Doctor go to protect his companion?
第 18 集 The Caves of Androzani (2)
播出时间：1984年3月10日
The Doctor and Peri have been rescued from the firing squad by the mysterious Sharaz Jek. But he has his own plans for them. And why are they suddenly feeling ill?
第 19 集 The Caves of Androzani (3)
播出时间：1984年3月16日
The situation on Androzani Minor is building toward a violent confrontation. And the Doctor and Peri are slowly succumbing to spectrox toxemia.
第 20 集 The Caves of Androzani (4)
播出时间：1984年3月17日
Events on Androzani reach a bloody climax. Will the Doctor and Peri survive the carnage? And at what cost?
第 21 集 The Twin Dilemma (1)
播出时间：1984年3月23日
Earth, the future. The genius Sylvest twins, child prodigies, are kidnapped by the mysterious Professor Edgeworth and taken to the planet Jaconda. But who is Edgeworth? Why does he serve the giant slug Mestor? And what is Mestor's plan?
第 22 集 The Twin Dilemma (2)
播出时间：1984年3月24日
The Doctor takes Peri to Titan 3, a desolate hunk of rock in space where he hopes to find some solitude for awhile. Instead he finds the lone but unconscious survivor of a recent spaceship crash in sight of a mound-shaped complex where no formalized structure should exist.
第 23 集 The Twin Dilemma (3)
播出时间：1984年3月30日
The Doctor arrives on Jaconda, once lush and green, to find it completely devastated by giant gastropods. Old legends about the planet's half-human/half-slugs weren't just myths after all. With or without help from the Doctor and his unpredictable mood swings, Lt. Lang is up for rescuing the twins, who are finally informed of the grand purpose they've been brought to Jaconda to accomplish.
第 24 集 The Twin Dilemma (4)
播出时间：1984年3月31日
The Doctor and Edgeworth deduce that the real plan of Mestor, the gastropod ruler of Jaconda, will not only destroy Jaconda but lead to the devastation of other planets. Together they hope to thwart him despite his formidable ability at slipping into people's minds and controlling them.
