"It has been 14 years since the Martians invaded England. The world has moved on, always watching the skies but content that we know how to defeat the Martian menace. Machinery looted from the abandoned capsules and war-machines has led to technological leaps forward. The Martians are vulnerable to earth germs. The Army is prepared. So when the signs of launches on Mars are seen, there seems little reason to worry. Unless you listen to one man, Walter...

The very far future: The galaxy is a drifting wreck of black holes, neutron stars, and chill white dwarfs. The age of star formation is long past. Yet there is life here, feeding off the energies of the stellar remnants, and there is mind, a tremendous galaxy-spanning intelligence each of whose thoughts lasts a hundred thousand years. And this mind cradles memories of a long-gone age when a more compact universe was full of light. The twenty-seventh...

The wheel of ice is a ring of ice and steel turning around a moon of Saturn. It is home to a colony mining minerals for a resource-hungry future Earth. Aboard the wheel the second Doctor, Jamie, and Zoe find a critical situation and three strangers who have just turned up out of nowhere look like prime candidates to be accused of sabotage. The Doctor finds himself caught up in a mystery that goes right back to the creation of the solar system.

Four hostages are finally released, but they face a world suddenly inundated as vast amounts of water is released from the earth's mantle. As the world's cities and countries disappear under the rising seas, humanity faces unimaginable global disaster.

What would happen to the world if the sun went out? By the middle of the 21st century, humanity has managed to overcome a series of catastrophic events and maintain some sense of stability. Space exploration has begun again. Science has led the way. But then one day, the sun goes out. Solar panels are useless, and the world begins to freeze. Earth begins to fall out of its orbit. The end is nigh.Someone has sent us a sign.