Doctor Who "The Ark in Space - Part Four" (1975)

The thrilling conclusion to the first proper serial of the Fourth Doctor continues to impress with the new TARDIS crew solidifying as a team and even manages to link into the next serial as "Robot" did with this one. Noah has completely transformed into a Wirrn, but still maintains some aspect of his former self as he speaks while the other Wirrn are mute. His feelings for Vira are still strong as he tries to appeal to her directly, possibly playing on her emotions, rather than through the Doctor who is clearly the spokesman for the group. He even permits the group safe passage off the ark, leaving the remaining humans still in suspended animation for the Wirrn to use as hosts. It is only his love for Vira that has led to his human mind being able to hold on. The proof of that comes from the fact that even though Dune was also absorbed, we never hear from that character.

Tom Baker continues to impress as the new Doctor and there is no doubt that this is essentially the same man as his previous three incarnations. Despite being able to leave in the TARDIS any time he pleases, he has an obligation to stay and save the remnants of humanity from being used as Wirrn hosts. He has come a long way from the First Doctor who was very much the anti-hero who did not want to become involved in local matters. The writers were forced to strand the TARDIS crew at their new destination to force their involvement. Over the years the Doctor has become a much more proactive hero and stepped into the fray even at the danger to himself or his companions. Perhaps the Third Doctor's exile has led him to have a better appreciation for humans because from this point forward, he tends to always side with them no matter what the situation.

Sarah Jane is given the most to do in this episode as it is she who comes to the conclusion that the colony ship's power supply could be used to protect the cryogenic chamber. The Doctor continually cuts her off before finally coming around to hearing what she has to say which is a great comedic bit. She also volunteers to undertake the dangerous task of crawling through the air shafts in order to run the cable necessary to electrify the cryogenic chamber's perimeter to keep the Wirrn out. Unfortunately the elevation of Sarah Jane has led to Harry being slightly sidelined as he spends most of his time with Vira and Rogin (Richardson Morgan) in the colony ship. He continues to amuse with his babbling personality and I just hope in the next few serials both companions can take equal roles in the adventures.

Despite the unrealistic look of the Wirrn, they may just be some of the most vicious of the Doctor's foes as they appear quite unstoppable. The horrifying intent for humanity has already been covered, but here we see there is little that can be done to defeat them. The Doctor only manages to hold them off from the humans still in hibernation and if it were not for Noah's sacrifice it's quite possible the Wirrn would have succeeded in their mission. Eventually they would have found a way into the cryogenic chamber as our intrepid band was about to have their oxygen supply cut off. The Doctor of course never panics or gives the impression that hope is ever lost as he even tells Sarah Jane it's her imagination that the room is getting stuffier.

More Alien/Aliens parallels: the romp through the air vents, blasting the attacking Wirrn with the ship's engines and the unrelenting, mass attacks of Wirrn that could strike at any moment. This serial succeeds in setting a new darker theme for Doctor Who as the producers set out to do when they took over at the beginning of this season. The dangers are very real and the menaces truly terrifying. On to see what the Earth after 10,000 years of abandonment holds for our TARDIS gang.

Favorite moment: Constantly getting stuck in the shaft she is crawling through, the Doctor goads Sarah Jane into action by telling her that they never should have relied on a silly girl for such an important task. Sarah Jane's feminist mentality takes over and she scratches her way out of the vent for nothing else than to give the Doctor a hard slap. The Doctor silently giggles as she grows angry which heralds a change from the more fatherly Third Doctor who probably would never had treated his companions in such a manner, even for the greater good.