Search Worlds Without End

"They've been fighting this war for longer than man has been walking upright, and they don't take prisoners."

The war between the Sontarans and the Rutans has been raging for millennia. Billions have died and whole star systems have been obliterated in the conflict. Now, finally, one side may have victory within its grasp.

The human colony world of Raghi is crucial to that victory. When the Fifth Doctor and Turlough arrive there, they find a seemingly stable society ruled by a strict caste system. But all is not as it seems. Members of the lower caste are being struck down by a mysterious illness. People are vanishing in their hundreds. And strange objects have been observed orbiting the sun.

Why is Raghi so important to the feuding alien empires? And how high a price will the galaxy pay if the conflict comes to an end?

"They say a journey of a thousand miles begins with but a single step. If I'm right, then a journey of a thousand miles will take but a single step."

The search for the fourth segment of the Key to Time brings the TARDIS to 1930s Shanghai: a dark and shadowy world, riven by conflict and threatened by the expansion of the Japanese Empire. Meanwhile, the savage Tongs pursue their own mysterious agenda in the city's illegal clubs and opium dens.

Manipulated by an elusive foe, the Fourth Doctor is obliged to follow the Dragon Path -- the side-effect of a disastrous experiment in the far future.

But would two segments of the Key be on the same planet? Is the Black Guardian behind the dark schemes of the beautiful Hsien-Ko? And who is the small child who always accompanies her?

"He's one of my own people, Victoria, and he's hunting me."

Darkheart: a faded neutron star surrounded by dead planets. But there is life on one of these icy rocks -- the last enclave of the Earth Empire, frozen in the image of another time. As the rest of the galaxy enjoys the fruits of the fledgling Federation, these isolated imperials, bound to obey a forgotten ideal, harbour a dark obsession.

The Doctor, Jamie and Victoria arrive to find that the Federation has at last come to reintegrate this lost colony, whether they like it or not. But all is not well in the Federation camp: relations and allegiances are changing. The fierce Veltrochni -- angered by the murder of their kinsmen -- have an entirely different agenda. And someone else is manipulating the mission for his own mysterious reasons -- another time traveller, a suave and assured master of his work.

The Doctor must uncover the terrible secret which brought the Empire to this desolate sector, and find the source of the strange power maintaining their society. But can a Time Lord, facing the ultimate temptation, control his own desires?