The Inhabitants of the Ark Watch the Uninvited Guests

The TARDIS materialises on a giant spaceship some ten million years in the future at a time when the Earth is about to plunge into the Sun.

As they explore the time travellers are unaware at first that they are onboard a spaceship carrying all the Earth's surviving plant, animal and human life (much of it miniaturised and in suspended animation) and when they do, Dodo names the ship The Ark.

They learn that The Ark is on a 700 year voyage to colonise the planet Refusis II so as to start a new home for the human race. The also realise that as well as humans, on board The Ark are the Monoids – a mute, subservient race who have a single eye. The Monoids seem to be more than willing to tend to all the human crew’s needs. And to help pass the time during the journey they are being used to create a vast statue depicting a human being.

Dodo Sneezes

However, Dodo is suffering from a cold - an unknown affliction in this era - and as the human Guardians of the ship and the Monoids have no resistance to this ancient virus and despite the efforts of their medical staff, led by Rhos, a plague soon breaks out.

Things though get far worse when the Commander of The Ark collapses the whole ship is placed on alert. The Deputy Commander is suspicious of the travellers and believes they have deliberately infected the ship. Then the first Monoid dies and there is little The Doctor can say to pacify the angry Guardians.

The Commander of the Ark

Placed on trial for their crimes The Doctor, Steven Taylor and Dodo try to defend themselves but the trial is going against them. It is only when Steven himself succumbs to the infection the ailing Commander intervenes to protect the three travellers and permits them access to medical equipment to devise a cure to the cold. The Doctor is fortunately able to develop one, and so he and his companions are allowed to return to the TARDIS and leave.

This seems to be the end of this particular adventure, but a surprise is in store as the TARDIS immediately re-materialises in what appears to be almost exactly the same place. However, The Doctor, Steven and Dodo soon discover that they have in fact returned to the ship at the end of its voyage.

Things though have changed - partly as a result of the earlier plague, the Monoids, have now grown strong, staged a coup during the long journey, have voice communicators and have enslaved all the humans. The Monoids have also completed the statue but instead of depicting a human being it is now in the image of themselves.

Doctor Searches for a Cure

When The Ark arrives at Refusis II The Doctor discovers that the Monoid leaders plan to colonise the planet just with themselves with none of the humans. But not all of the Monoids are happy about this and the switch in roles - and so a revolt between the Monoids takes place. It is then that The Doctor learns of a bomb that has been placed inside the statue that the Monoids plan to use to destroy The Ark and all of the humans.

The humans begin to land on Refusis II and, along with the remaining Monoids are offered peaceful settlement - having been offered support on peaceful terms by the Refusians.

The TARDIS then departs. But Steven and Vicki are shocked when The Doctor simply vanishes from the TARDIS control room…