I think the lesson from this story is that laughter is contagious.  Jenny is an adorable, sweet little mouse and Lorenzo is a mouse-eating cat.  Jenny is bound and determined to meet this Lorenzo, whom she has heard so much about.  Strangely enough, her parents let her go with a warning of ‘be careful!’  They meet and Jenny laughs, sings and dances and turns a backward somersault, totally befuddling Lorenzo, who breaks out laughing.  Enjoying Jenny’s good humor was much better than enjoying her as a snack, they became the best of friends.