The Tardis materialises on board the maiden voyage of a pioneering space cruiser, travelling from Earth to the planet Eternity. The Doctor has just started exploring the huge, hi-tech Interstitial Transposition Vehicle when there is a loud bang, a massive jolt and a flash of light. Shortly afterwards, he discovers that nearly all the passengers and crew have disappeared.
When the TARDIS is invaded by a holographic marketing scam, the Doctor and Donna find themselves trapped on the Edifice, a purpose-built complex of luxury apartments in space. Their new environs leave much to be desired: millions of beings from across the Universe have been gathered to live side by side in similar apartments. Instead of creating neighbourly affection, it's led to terrible battles being waged in the corridors and on the stairwells.
Across Cardiff, ordinary people are behaving in odd ways: saying hello to one another, and going out of their way to greet people. Torchwood discovers that an alien communications field is gathering strength in the city. The team must find the device responsible and shut it off-before civil unrest engulfs the city.
The End of the World began on a Thursday night in October, just after eight in the evening… The Amok is driving people out of their minds, turning them into zombies and causing riots in the streets. A solitary diner leaves a Cardiff restaurant, his mission to protect the Principal leading him to a secret base beneath a water tower. Everyone has a headache; there's something in Davey Morgan's shed; and the church of St Mary-in-the-Dust, demolished in 1840, has reappeared – though it's not due until 2011.