At the instant of apocalypse, the entire history of the British Empire changes.
Charles Babbage completes his Analytical Engine, and sets the stage for an increasingly insane Lord Byron to return the Empire to its former glory - by invading the Thirteen Colonies.

Episode Synopsis

After an end-of-the-world party in a rural pub, a young man's girlfriend disappears in front of his eyes - and then things continue to get worse.
In the nearby city, an eccentric physicist finds a strange note, and sets off through the anarchic streets of a Cathedral city in Northern England to find them.