Miss Bianca, a white mouse of great beauty and self-confidence, travels with the ambassador's son to Norway on behalf of the Prisoner's Aid Society in a perilous mission to rescue a poet imprisoned in the dreadful Black Castle.
As Perpetual Madam President of the Mouse Prisoners' Aid Society, Miss Bianca must try to save the life of a young court page sentenced to death by the heartless Ranee of the Orient.