Bern, a pet rat lost on the wild streets of London, must struggle to find enough food for himself, and to pay off the Rat Father's soldiers who demand their cut. His rat buddy Ratsby suggests a dance number to con tourists out of food in Green Park. Before they know it, they have a circus on their hands, complete with tumbling mice, dancing geese, acrobatic squirrels, and a daredevil leap. They also caught the attention of the Rat Father, the Squirrel King, and the Ravens of the Tower of London. All who have ideas of their own about who should run the circus. Hungry falcons, firebug weasels, and hoarder cats descend on them. It will be a miracle if the circus makes it through the first act.