Production Code: 4C
1 - 25/01/1975 17:35
2 - 01/02/1975 17:30
3 - 08/02/1975 17:30
4 - 15/02/1975 17:30
The TARDIS arrives on an apparently deserted and deactivated space station Nerva, otherwise known as the Ark, orbiting Earth in the far future. There the Doctor, Sarah and Harry discover the last survivors of the human race held in suspended animation, Earth having been evacuated thousands of years earlier when solar flares threatened to destroy all life.
The station has been visited by a Wirrn, an insect life form, which has laid its eggs in the solar stacks and absorbed the body and mind of one of the sleeping humans. The Doctor's reactivation of the station's systems causes the humans to start to revive. Their leader, nicknamed Noah, becomes infected by one of the emerging larvae and is slowly taken over.
The Doctor and his friends meanwhile gain the trust of the other humans, now led by a med-tech named Vira. Together they manage to lure the hatched Wirrn insects into a shuttle craft and then eject it into space.
In a final act of humanity, Noah - by this time fully transformed into a Wirrn - deliberately neglects to set the shuttle's stabilisers, causing it to explode.
Sarah has inadvertently been placed in suspended animation with the other sleeping humans. Harry searches in some cupboards for a resuscitation unit with which to revive her. The first is empty, but when he opens the second, a huge green insect lurches towards him.
A revived human named Libri goes after Noah, who is acting strangely. Noah persuades Libri to hand over his gun and then shoots him. Turning, Noah pulls his left hand from his pocket and stares at it in horror. It is engulfed in a green, larva-like skin.
The Wirrn turn off the Ark's main power and the Doctor heads for the solar stacks to try to reconnect it. There he finds numerous Wirrn hanging in chrysalises. He is about to turn on the power when he is confronted by a fully grown Wirrn creature with Noah's features still just visible. As he watches, Noah's face vanishes to be replaced by that of the Wirrn adult.
The Doctor decides to pop down to Earth using the Ark's transmat system to ensure that the diode receptors are in good working order to receive the returning sleepers. Sarah and Harry go with him.
The Quatermass Experiment (Noah's mutation and the Wirrn's stealing of memories).
Quatermass and the Pit.
Dr Strangelove (Noah fighting his own arm).
It! The Terror from Beyond Space.
Voyage of the Space Beagle.
The Doctor : "Homo sapiens. What an inventive, invincible species. It's only a few million years since they crawled up out of the mud and learned to walk. Puny, defenceless bipeds. They've survived flood, famine and plague. They've survived cosmic wars and holocausts. And now, here they are, out among the stars, waiting to begin a new life. Ready to outsit eternity. They're indomitable."
The Doctor : "It may be irrational of me, but humans are quite my favourite species."
Harry : "Fancy a member of the fair sex being top of the totem pole."
Harry : "Independent sort of bird, isn't she?"
Noah : "Your resistance is useless!"
Vira : "You claim to be med-techs?"
The Doctor : "Well, my doctorate is purely honorary, and Harry here is only qualified to work on sailors."
The Doctor : "Inch it round your end."
The Doctor's scarf was knitted by Madame Nostradamus. He carries a cricket ball. Humans are his favourite species.
Harry caught his nose in a sliding door in Pompey barracks. Sarah hates brandy, which the Doctor keeps in the TARDIS.
The Wirrn are natives of the Andromeda galaxy, who lived on herbivores until the humans arrived and fought them for 1000 years, driving them out. [A vast conflict that Noah may be overstating.] When they take over a person, they absorb their memories into the group mind. Individuals thus infected give out a subconscious impression of something alien [via pheromones]. Their life cycle doesn't necessarily need a host, but they use Noah to bypass the pupal stage.
Space station Nerva, in Earth orbit.
Nerva was built in the late 29th or early 30th century under a female High Minister, this story being set many thousand years later when it is being used to escape the solar flares that decimated Earth. Rogin refers to trade unions in a reference to demarcation disputes.
No one but the regulars takes part in the action of the first episode - the only instance of this occurring after season one's Inside the Spaceship.
The Doctor uses his yo-yo to take a gravity reading, and a cricket ball to try to hit the switch controlling the Ark's defence systems.
The Ark in Space shares a number of ideas with the season three story The Ark.
Humanity in the future is divided into functional groups, like insects, but Rogin wakes up as a fully fledged Holmes wide boy.
The slime trail which the Doctor and Harry chance upon is clearly visible to the audience from the start of the scene.
One of the frozen humans can be seen blinking.
Sarah's knickers are visible in episode one.
Can all of the Wirrn really fit into that small cockpit?
Why doesn't the Doctor want to wake everybody up and take them to Earth in the TARDIS? His reasons make it sound like he's just making the game more interesting.
Why are there only three transmat pads when there are millions of people on Nerva?
Why doesn't the Doctor go down in the TARDIS, as the transmat is faulty (and possibly dangerous)?
The entire population of Earth are wearing flares. (No wonder there's all that panic about 'stacks' and 'flares'.)
Cast & Crew
The Doctor - Tom Baker
Harry Sullivan - Ian Marter
Sarah Jane Smith - Elisabeth Sladen
High Minister's Voice - Gladys Spencer
Libri - Christopher Masters
Lycett - John Gregg
Noah - Kenton Moore
Rogin - Richardson Morgan
Vira - Wendy Williams
Voices - Gladys Spencer
Voices - Peter Tuddenham
Wirrn Operator - Stuart Fell
Wirrn Operator - Nick Hobbs
Director - Rodney Bennett