The Armageddon Factor
The Armageddon Factor is the sixth and final serial of the 16th season of the British science fiction television series "Doctor Who", which was first broadcast in six weekly parts on BBC1 from 20 January to 24 February 1979. It was the last to feature Mary Tamm as Romana. The serial is set on the planets Atrios and Zeos, and another planet in between them. In the serial, the war between Atrios and Zeos is nearing its end. Mentalis, a commandant computer on Zeos, and the Marshal of Atrios (John Woodvine), plot to wipe each other out . At the same time, the Shadow (William Squire), a henchman of the Black Guardian (Valentine Dyall), steals the time and space vessel the TARDIS, which contains the first five segments of the powerful Key to Time, and kidnaps Princess Astra of Atrios (Lalla Ward), who is the sixth and final segment. Plot. Searching for the final segment of the Key to Time, the Fourth Doctor and Romana arrive on the planet Atrios, which has endured a recent bombing by their neighbouring planet Zeos, with whom they are at war. The Marshal of Atrios is about to launch a counterstrike on  Zeos, but the Doctor finds that Zeos is deserted save for the giant computer Mentalis, which is controlling the war. He also discovers that the true opponent is a third planet called the Planet of Evil, ruled by "the Shadow". The Shadow, an agent of the Black Guardian, has Princess Astra of Atrios captive, threatening to torture her if she doesn't give him the location of the final segment of the Key to Time (which she doesn't know). After disabling Mentalis, the Doctor discovers that it has a failsafe built in that will obliterate both Atrios and Zeos  in the event of a successful strike against Zeos. With the assistance of Romana and K9, the Doctor creates a substitute sixth segment out of chronodyne, which gives the Key enough power to create a time loop in which to trap the Marshal's ship (armed with missiles for the final strike) as well as the Mentalis control room. On the Planet of Evil, the Doctor encounters another Time Lord, Drax, who he last met at the Academy. Drax has been employed under duress by the Shadow but agrees to help the Doctor. During this encounter, Drax refers to the  Doctor as Theta Sigma. The Shadow wants the Key for himself, and forces the Doctor to retrieve it for him. The Doctor leads a servant of the Shadow, known as a Mute, to his TARDIS and opens the door, but is suddenly shrunk to tiny size by Drax, who then shrinks himself using the dimensional stabiliser from his own (in-need-of-repair) TARDIS. Drax had misinterpreted the Doctor's plan and shrank the Doctor instead of the Mute. The Mute returns to the Shadow with the Key, and the Doctor realises why the Shadow has requested it: Astra is  the final segment, and is transformed in front of everyone. Using their diminished size, the Doctor and Drax smuggle themselves into the Shadow's lair inside of K9, who pretends to still be under the Shadow's power. Drax again uses the stabiliser, this time to return them to their normal size. The Doctor snatches the partially assembled Key and the final segment, and disappears with Romana and K9 in the TARDIS, assembling the Key after setting up a shield around Zeos to deflect the Marshal's missiles towards the Shadow's base, destroying it. The White Guardian appears to  congratulate the Doctor on finding and assembling the Key to Time, and requests that it be sent to him. However, the Doctor, realising that it is actually the Black Guardian in disguise—due to his lack of compassion for the fate of Princess Astra—orders the Key to re-disperse. Enraged, the Black Guardian threatens to kill him. In an attempt to evade him, the Doctor fits a randomiser into the TARDIS guidance system, sending it to an unknown location in time and space, leaving the Doctor with no idea of where they are headed, and the Guardian being unable  to follow. Production. Working titles for this story included "Armageddon". This story was the last that Bob Baker wrote with Dave Martin. Baker's next story, "Nightmare of Eden", would be a solo effort. In the original draft of the script, the Black Guardian did not appear at all. He was only inserted in the later drafts by incoming script editor Douglas Adams and producer Graham Williams. Broadcast and reception. Twenty-three minutes into transmission of Part Five, a technical breakdown resulted in the episode going off the air for fifty seconds. The break occurred at the point where the  Doctor is being escorted to the TARDIS by the Mute; and the Shadow makes to remove his control device from Princess Astra, saying "Now, my Princess, your work is done. Your destiny is at-". Music was played ("Gotcha" by Tom Scott, better known as the theme music to ABC's "Starsky & Hutch") and a "TEMPORARY FAULT" caption slide displayed until the fault was rectified. When transmission restarted, the videotape had been slightly rewound so there was a repeat of the action immediately prior to the break—with the Shadow's line also finally completed as "Your destiny is at hand ." A reconstruction of the break can be found as a bonus item on the serial's remastered DVD release. This was the final serial of the original series to be broadcast in six parts. Paul Cornell, Martin Day, and Keith Topping gave the serial an unfavourable review in "The Discontinuity Guide" (1995), describing it as "a dreary end-of-season Oh-my-God-the-money's-run-out 'spectacular'" without subtle acting. In "The Television Companion" (1998), David J. Howe and Stephen James Walker wrote that "The Armageddon Factor" was "entertaining enough in itself, with some good direction by Michael Hayes  and generally fine production values, but ultimately fails to tie up all the loose ends and leaves the over-arching plot strangely unresolved". They praised the Shadow but felt that the other characters were one-dimensional, and called the ending a "cop-out". In 2011, Patrick Mulkern of "Radio Times" stated that the serial "hugely disappoints, yet it's not an unmitigated disaster". He criticised the characterisation and much of the plot, but praised the direction and the Shadow. On the other hand, DVD Talk's Justin Felix gave the serial four out of five stars, saying that it "packs  more of a wallop than the previous two stories" and had everything typical of "Doctor Who". Felix also called it Mary Tamm's best performance. Commercial releases. In print. Terrance Dicks' novelisation was published by Target Books in June 1980. A typo has the Marshall introduce himself as the warlord of Zeos, instead of Atrios. An Audiobook of the Target novelisation was released on 6 June 2019 read by John Leeson. Home media. It was released on VHS on 5 June 1995. Along with the rest of season sixteen, it was released on DVD in North America as part of  the "Key to Time" box set in 2002, only available in Region 1. A remastered limited edition "Key to Time" box set was released in Region 2 in the United Kingdom on 24 September 2007. It contains more extras than the previously released US set. This remastered set was released in Region 1 on March 3, 2009.