Dick and his cat Calico have arrived in London Town, seeking to make their fortune, only to find that they are not welcome. However, Alderman Fitzwarren's daughter, Alice, persuades her father to give Dick a job, while Calico is taken on to help Tapioca Dripping, the cook, keep marauding rats out of her pantry. Captain Cockleshell and Salty Swab, the captain and mate of the good ship The Unicorn, arrive to collect their orders for the next trading voyage, only to be tricked out of part of the cargo by Snitch and his rascally band of rats; Dick and Calico, turn the tables, trick the rats and recover the cargo. Phobia, Fitzwarren's wife, sees Calico's money making potential and devises a scheme to pay Snitch and his rats to cause mayhem and then she will send in Calico to get rid of the rats in return for a big reward. All she needs is somewhere to try out her little scam - the answer is the rich kingdom of Barbary, exactly where Fitzwarren and his cargo will be heading. Will Calico cooperate? Will Fitzwarren and his crew escape Black Berry and his pirates? Will Dick foil Phobia's evil plan and win Alice's hand? All is revealed in this fun and fast moving tale.