Most children at some point think about what they will be when they grow up. Will they be a teacher, an athlete, a writer, an actor, a policeman, a dancer, a fireman, a priest, etc.? This is an imaginary story about the daily lives of Leo and Lou, brother and sister field mice, and their family. In playing together Leo and Lou suggest occupations and professions they imagine for themselves: a nurse, a cowboy, a pilot, a ballerina, an author, etc. As mama and papa learn of their interests, the mama reminds them of the saying: "Be what you want to be."