Byzantium!

When the TARDIS arrives in 64 AD, close to the ancient capital of Byzantium, Barbara is thrilled at the prospect of a glimpse of the Roman Empire at its height. But the Doctor warns of the brutality and corruption to be found behind its civilised veneer. And he is proved only too right...

Split up in a terrifying market-place brawl, the companions find themselves dispersed among the rival cultures that uneasily share the city. Barbara with the zealous Jews, Ian finding his feet amongst the divided Romans, Vicki, adopted by the kindly but exasperating Greeks, and the Doctor, helped by (and helping !) the gentle Christians, all believe that the rest of their party has been killed, and they are left alone to cope with the complex culture-clashes of this often barbaric city.

But even if they do reunite, their troubles are not necessarily over. After all, they have to reach the TARDIS before they can actually leave Byzantium. And in this shifting world, can it be relied upon to remain in one place?