On page 4 of the book, Mrs. Frisby, a field mouse, is described as a widow, as her husband, Mr. Frisby, died the summer before. Mrs. Frisby is now the head of the house, and she is able, through her diligence, to raise her four children alone. The family survives, though it is difficult for them in the coldest months of the winter, as the beans and black-eyed peas have been ravaged by birds and the asparagus roots are frozen. The family lives in an underground house in the garden of a farmer named Mr. Fitzgibbon, and they have lined their house with soft objects such as leaves, grass, and cotton so that it is warm and dry. The reader learns a bit about Mr. Frisby. For example, on page 15, Timothy, one of Mrs. Frisby's children, is described as thoughtful, a trait that he shares with his deceased father.