"Mildred," said Father Muskrat, "it is true that Harvey is selfish and inconsiderate, but he is not stupid and no-good. Mildred is loudmouthed and bossy," Father said to Harvey, "but she is not mean and rotten."

When Mildred goes off to a big party where little brothers are not invited, Harvey finds a secret club in a secret place where big sisters are not allowed to be members. But when Harvey's lonesomeness overpowers his stubbornness, he discovers that a secret club with two members is much better.