Basil, the rodent Sherlock Holmes, investigates the kidnapping of a toy-maker and uncovers its link to his arch-enemy, Professor Ratigan. In Victorian London, England, a little mouse girl's toymaker father is abducted by a peglegged bat. She enlists the aid of Basil of Baker Street, the rodent world's answer to Sherlock Holmes. The case expands as Basil uncovers the crime's link to a plot against the Crown itself.