In this story, Mrs. Frisby's son, Timothy, gets sick and she need to help him get better or he will die. Finally she is directed to the rats of NIMH, who her husband died helping, to help her move her home somewhere safe and warm. These genetically engineered and escaped rats help her because they owe her for her husband's sacrifice. Mrs. Frisby goes to many lengths to save her son, and ultimately, it pays off. They get their home moved in time and Timothy lives. The rats of NIMH are forced to leave though because scientists are after them and Mrs. Frisby doesn't see them again.
