After the misadventure at Hampton Court Palace, the London Bus tells Beatrice he will never drive into a building again. But when the Queen sends them both an invitation for tea at Buckingham Palace, the London Bus changes his mind. There's a problem, though - the Bus is too big and needs to be resized. He needs the help of the sloppy Magician with the 1000 Hats before the royal invitation turns into a nightmare. Then they receive another important invitation; this time to a royal horse-racing event where the London Bus gets unexpectedly horsed around while Beatrice becomes ... famous! Now the sky is the limit. Beatrice arranges a bizarre exchange programme between Westminster Palace and London Zoo, but short-sighted MI6 spoils it all. And there's more trouble a-brew in the city - London Eye gets miffed with the fiery Mayor and goes on fun-strike! Beatrice must sort out the argument and win the best cabin party in the sky before the impossible happens ...