Synopsis: When a Time Lord gets addicted to a British sweet, there's little wonder why he keeps popping up in England. Stopping off in a small village to pick up some more jelly babies, the Doctor is surprised to find the town overrun by Roman Legions. They have slipped into the "real" present through a dimensional shunt from an alternate present where the Roman Empire never fell. Closer examination reveals these Legionnaires to be robotic.
After being thrown to the arena and briefly enslaved for failing to give up the secrets of the TARDIS, the Doctor makes his way to the Imperial palace, which turns out to be an alien spacecraft.
Now realizing that this "Rome" is not at all the Rome of history, he encounters the secret of its longevity in this alternate reality. The Malevilus--a dreadfully evil alien race--took on the form of Roman Gods long ago, and are controlling this Rome through the introduction of alien technology as the "will of the gods". That knowledge, though, comes at a perilous price . . .