If the multiverse exists, it contains an infinite number of versions of the world we know. Welcome to the parallel world where the Roman Empire still exists - a world with many similarities to the one we know and take for granted, but with major differences.  Citizens have expiry times – the pre-determined dates for the end of their lives. The economy depends on slavery, but it is now called ‘indenture’. Order is maintained by the Security Council, whose agents have seemingly unlimited powers.

When Dave discovers that there is a parallel world where these impositions do not exist, he starts investigating. He drags Liz into the puzzle, but together they quickly discover that the Empire does not tolerate such threats to the status quo.