Olivia Flaversham is a young female sentient mouse.
Olivia is the daughter of toymaker Hiram Flaversham, whose mother seems to have passed away longer ago than Olivia can recall, possibly in childbirth. After her father was abducted by Professor Padraic Ratigan as part of one of the criminal mastermind's evil schemes, she asked Doctor David Q. Dawson for help, and with the help of Basil of Baker Street, they solved the case and got Mr Flaversham back. Olivia developped a strong bond with Dawson and Basil and often came back to visit, while also doing investigations of her own.
Olivia is youthful and sweet, easily fascinated by elaborate toys. She has a way with animals, such as basset hound Toby, and, in a fashion that is most caracteristic of a girl her age, is prone to violent emotional outbursts, be it suddenly crying or, on the opposite end of the spectrum, getting extremely playful in very awkward situations. Olivia has, however, also been shown to be very brave for her age, first evidence by her facing Ratigan when he had taken her hostage and daring to confront him and insult him, and later by her making investigations of her own with the help of Toby and a reformed Fidget some time afterwards.
After her appearance in the original movie, she has only appeared in The Sideshow Sea Beast.