The Great Mouse Detective(1986)
In the year 1897, a day before the Queen's diamond jubilee, a kidnapping occurred. Olivia Flaversham's father, Hiram, was taken away by a peg-legged bat. Olivia then seeks the help of Basil of Baker Street, the Greatest Detective of all Mousedom. With the help of Dr. David Q. Dawson, Basil attempts to close this case and succeed in defeating his greatest enemy, Professor Ratigan. Unfortunately, Ratigan has a plan to take over the monarchy and destroy Basil in the process. If you want to know more, you will simply have to watch the movie for yourself! :)
1992 TV spot
UK VHS Trailer
I actually got this off of youtube.