Parts: 10
Writers: Terrance Dicks, Malcolm Hulke
Airdates: 19 April 1969 - 21 June 1969
Production Code: ZZ

Doctor: second
Companions: Jamie, Zoe

Megalomaniac of the Week: War Lord
Special Guests: the Time Lords

Story: A muddy bomb crater, barbed wire and loud explosions greet the TARDIS crew upon their landing. The Doctor's theory that they have landed in the worst war in human history is confirmed when they are captured by two uniformed Germans. Fortunately they are rescued by British officers - but when the Doctor tries to leave the British camp and return to the TARDIS, the officers suspect he is trying to cross the German lines. Suddenly, and for no reason, the TARDIS crew become suspicious - Jamie is accused of deserting his Highland regiment, and the Doctor and Zoe are accused of espionage.

With a death sentence looming for the Doctor, the TARDIS crew are only too happy to escape the camp - but as they flee in a stolen ambulance, they cross through a thick mist...and when they emerge through the other side, all the sounds of battle have disappeared. But the peace is short-lived - soon an army of Roman troops charges them...

It soon becomes clear that the Doctor, Jamie and Zoe have not landed on Earth at all, but rather on an alien planet divided into several different war zones. Soldiers from throughout Earth's history have been brought to the planet to fight their wars on alien soil - but why? Who is behind the scheme? And how have they managed to transport soldiers from different time zones? When the Doctor discovers the answers, he learns that he may have to sacrifice far more than usual in order to put things to rights...