There are lots of unhappy kids in young fiction, but Martha chooses a novel way to express her anguish. The family scapegoat and klutzy younger sister of crack athletes whose praises her parents incessantly sing, Martha is torn away from Harriet, her new and only friend, and sent off under protest to the camp her sisters had enjoyed. While there, Martha shuns all game and sports, reads constantly in the fantasy and mythology genre to which she's addicted, and becomes an object of ridicule for constantly carrying around an empty shoebox, a friendship token from Harriet. Only on the bus home does Martha, now called Moose by fellow campers, become a part of cabin six; but it's arriving home to discover that Harriet has a new, exclusive best friend that triggers her transformation into a creature who galumphs around in homemade antlers and gives moose calls instead of speaking. Meeting a new, bookish kid who shares her reading tastes helps, though, and much parental worry later an unexpected glimpse of herself prompts Martha to cast aside her antlers and assume the role of Diana. Though the parents' insensitivity and Harriet's chumminess are overdone early on, this will be forgiven for the sympathetic picture of one camper who doesn't adjust in the end--and for troubled Martha's expressive way of acting out her feelings about herself.