Mouse. In Disney mice are good. Rats bad. (Protect the Mouse!)
Bob Newhardt does the voice of Bernard the mouse. Zaza Gabor does the voice of his blonde mouse companion.
They travel by sea gull from NY to a Louisiana swamp to rescue a kidnapped orphan from a scheming NY pawn shop owner (female) who forces her to work and risk her life in a cave complex under the swamp searching for a jewel in a pirate treasure that it contains and which floods during high tide. (Yes, a cartoon...)