The episode starts with a dead grandmother being taken over by a gaseous creature then killing her grandson before heading out into the snow. 

The Doctor and Rose travel back to Christmas Eve 1869, in Cardiff. After buying a newspaper and realising it isn't Naples 1860, they hear a scream come from a nearby theatre. Inside Charles Dickens had begun reciting his story A Christmas Carol when the Geith inhabiting the dead woman suddently escapes into the theatre.

The Doctor runs into the theatre to see it escape into the gas pipes. Rose sees two undertakers take the body of the grandmother into a hearse. She tries to follow them and is drugged, kidnapped then put in a room with two 'dead' bodies.

The Doctor grabs Charles' coach, dragging him along for the ride and they save Rose from two zombies about to kill her.

The Doctor finds out that these gaseous creatures are escaping a dying planet via a split in the fabric of space time. They're living in the gas pipes until they can take advantage of a recently dead body.

The girl who is one of the undertakers, has second sight and has been the bridge between one reality and the next.

The Doctor asks her to make the link and allow the rest to come through as he wants to save them. First a seance to get instructions, then down to the cellar to be at the focal point of the bridge. Unfortunately it all goes horribly wrong as the once innocent Geith suddenly transform into a massive invasion fleet. The Doctor and Rose are trapped in the cellar as one by one people around them are killed and taken over by the creatures. How do they get out of this one?

Rose, The End of the World The Unquiet Dead

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