An agreeable little story about eight-year-old Mitzi, whose archaeologist mother is about to marry a fellow professor. Mitzi is mildly unhappy about the situation, especially when Walter, her father-to-be, comes to dinner with his mother, who'll be living with them, his eleven-year-old son Frederick, who is maddeningly nice to Mitzi, and bothersome three-year-old Darwin, a genius who can read but is usually busy being a dinosaur. She is even angrier to discover that her mother is planning a five-week field trip and will take Frederick along but leave Mitzi home with Darwin. However, Mitzi takes some comfort in helping her friend, the old janitor at school who shares her fondness for motorcycles though Walter thinks they should be outlawed. (As Mitzi's friends, the janitor and his wife are invited to the wedding.) When the wedding day arrives, Darwin balks at performing his part in the backyard ceremony, and Mitzi shows her maturity by filling in for him. The occasion ends in a glow when Mitzi learns that she's now considered mature enough to be taken on the dig. Soft, but sympathetic in a good-natured way.