S4E8
Tragic with undertones of hope
Written by Gerry Davis
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The Tenth Planet Part 4

As the Cybermen plot Earth's destruction to save their dying planet Mondas, the Doctor thwarts their plans, but faces a mysterious transformation, leaving his companions stranded and his future uncertain.

At a South Pole tracking station, General Cutler intends to fire a rocket armed with a Zed-bomb at the approaching planet Mondas to eliminate the Cybermen. The Doctor arrives and attempts to dissuade him, but Cutler, bitter after losing his son, refuses to listen, and ultimately is killed by the Cybermen as they invade the base. The Cybermen, led by Krang, reveal their plan to destroy Earth because the close proximity of the two planets endangers both. They force the humans to disarm the rocket and move the warhead to the radiation room, taking Polly hostage during the process. Ben, Barclay, and Dyson, working to move the bomb, realize the Cybermen are afraid of radiation, and lure one into the radiation room, incapacitating him. They defend the room from further intrusion, preventing Cybermen from setting off the bomb.

Meanwhile, Polly is held captive on the Cybermen's ship where she is strapped to a chair, but Mondas nears destruction as it absorbs too much energy. After the Cybermen attempt to get Ben, Dyson, and Barclay to help them fuse the warhead by threatening Polly and the Doctor, Ben disconnects the communication system and formulates a plan to use the reactor rods in the room to trap the Cybermen. Dyson and Haines extract the fuel rods from the reactor, while Barclay monitors the radiation. Ben lures approaching Cybermen into a corridor where Haines and Dyson, wielding radioactive rods, cause the Cybermen to collapse. The remaining humans discover that Mondas has disintegrated, causing the Cybermen to collapse as well, because they were dependent on the planet for power.

With the Cybermen threat eliminated, contact is re-established with the outside world, and the immediate danger is over. Ben and others free the Doctor and Polly from the Cybermen ship. However, the Doctor insists they must leave immediately, showing a strange urgency. He abruptly departs, leaving Ben and Polly behind, and begins to transform inside the TARDIS, collapsing as his features change. Ben and Polly rush into the TARDIS finding the Doctor collapsed and changed, ready for a new adventure.


Events in This Episode

The narrative beats that drive the story

32
Act 1

The episode opens with the rocket's failed launch, prompting General Cutler's fury. He blames Barclay for sabotage and threatens the Doctor and Polly, demanding the Doctor be brought to him. A distressed transmission from Cutler's son, Lieutenant Cutler, warns of strange phenomena on Mondas before cutting out, coinciding with radar detecting approaching Cyberman ships. Cybermen land, swiftly killing Cutler as he attempts to shoot the Doctor, whom he blames for his son's presumed death. Krang, the Cyberman leader, takes command, forcing the humans to disarm the rocket and move its warhead to the radiation room. Polly is taken hostage to the Cyberman ship to ensure compliance. The Doctor, briefly communicating with Geneva, learns of global Cyberman landings. Krang then reveals the Cybermen's true objective: the destruction of Earth using the Zed-bomb to save their dying planet, Mondas. Ben, Barclay, Dyson, and Haines, tasked with moving the warhead, realize they have been manipulated into facilitating Earth's demise.

Act 2

Ben, Barclay, Dyson, and Haines, confined to the radiation room with the warhead, deduce the Cybermen's fear of radioactivity. Ben devises a plan, luring a Cyberman into the room where it collapses from exposure. They secure the room, preventing the Cybermen from setting off the bomb, and decide to wait for Mondas to disintegrate as the Doctor predicted. Krang, monitoring their progress, threatens the Doctor and Polly's lives if the humans do not fuse the warhead within three minutes. Ben, refusing to yield, disconnects the communication system to prevent further Cyberman surveillance and formulates a new, more aggressive strategy. He identifies the base's nuclear reactor rods as a portable source of radiation. Dyson and Haines extract the highly radioactive rods, while Barclay monitors the radiation levels, preparing for a direct confrontation.

Act 3

Ben lures Cybermen into a corridor. Haines and Dyson, wielding the radioactive reactor rods, ambush them from behind, causing the Cybermen to collapse. The immediate threat from the invading Cybermen inside the base is neutralized. Simultaneously, the approaching planet Mondas begins to disintegrate, observed by radar. This catastrophic event causes all remaining Cybermen to collapse globally, as their existence is entirely dependent on Mondas for power. Contact with the outside world is re-established, confirming the end of the Cyberman menace. Ben and the others swiftly free the Doctor and Polly from the Cyberman ship. The Doctor, exhibiting strange urgency and physical distress, insists on leaving immediately, abruptly departing in the TARDIS without his companions. Inside, he undergoes a mysterious transformation, collapsing as his features change. Ben and Polly rush into the TARDIS, finding the Doctor transformed as the ship dematerializes, signaling a new, uncertain chapter.