A young man working in a train station befriends a dog that can do amazing tricks. When the Queen of England is set to visit the station, an assassination attempt is put on her. Will the most unlikely of characters save the day?

Cyril and Shirley are a young, working-class couple who, in their struggle to make ends meet, have become absorbed in socialism. Cyril's sister Valerie and her husband aspire to a more privileged class. The only glue holding the siblings together is their withdrawn and wistful old mother.