Mrs. Brisby, a widowed mouse, lives in a cinder block with her children on the Fitzgibbon farm. She is preparing to move her family out of the field they live in as plowing time approaches, but her son Timothy has fallen ill, and moving him could prove fatal. Mrs. Brisby visits The Great Owl, a wise creature who advises her to visit a mysterious group of rats who live beneath a rose bush on the farm. She visits the rats and meets Nicodemus, the wise, mystical leader of the rats, and Justin, a friendly rat who immediately becomes attached to Mrs. Brisby.
