2015 год. Rex lives at the Tower of London and likes nothing better than sniffing around in juicy litter bins. But his favourite bin of all isn't just a litter bin – it's also a time machine. He jumps in and he's transported back to Hampton Court Palace during the English Civil War, where he meets Rogue, Charles I's favourite pet. Rogue tells Rex that her master is imprisoned somewhere in the palace. Can Rex help the King escape?