Mrs. Frisby is a widowed mouse (I didn’t know mice got married but oh well) with a sick child, the farmer (Mr. Fitzgibbon) whose garden she is living in is getting ready to plow up their home and he is too sick to move to the creek where they spend their summers (a summer house, these mice must be rich). Through a series of coincidences, she learns the rats living under the rosebush might be able to help her, and she learns how to approach them.
This is a children’s book. There are talking animals, although we are never told if they are talking in English or in little animal talk and the author is translating for us. The rats are intelligent, how they got that way is the story within the story.
Mrs. Frisby is the embodiment of a good mother. She is willing to do anything to save her child. She is also the embodiment of a good person, going out of her way to help other animals. She is also smarter than your average mouse.
The book gets to its expected happy ending, with a little sadness along the way, but not too scary or sad for grade school children.