The Rat Savior

Izbavitelj is a 1976 Croatian fantastic horror film directed by Krsto Papi. It was released in 1976, but won Best Film at the 1982 Fantasporto. The film was selected as the Yugoslav entry for the Best Foreign Language Film at the 49th Academy Awards, but was not accepted as a nominee.

A man uncovers a race of intelligent rats who can appear as human. He is captured and taken to the rat peoples leader the savior of the movies title. He escapes, but then wonders who among his fellow humans is a rat person in disguise.

Source: Wikipedia