Twins Scarlett and Thomas are learning about the Romans at school. So Grandad uses his time machine to send them back to Roman Britain. Scarlett finds herself in a Roman camp and is chosen as a slave by the Emperor Claudius's daughter, Antonia. The two become friends, and Scarlett witnesses both the glamour and the treachery of the Roman court. Thomas joins a rabble of local kids who hate the Romans - including a red-headed girl called Boudicca. Even when the gang is overwhelmed and taken as slaves, Bou remains defiant and rebellious. Will the twins find each other and escape, or will they both be stuck as Roman slaves for ever?