"What do you mean?" Judy asks her new friend, Clarissa Valentine. "How could you look in a mirror and not see your reflection?" When Clarissa insists that this strange thing has happened to her, Judy and the other girls think she is teasing them. But when Clarissa disappears in the middle of a television show, even Judy has to admit something peculiar is going on. The three other girls are angry, because with Clarissa went the twenty dollars they...