Nine-year-old Chris Leonard, who graduated from being Cathy's Little Sister on a trip to Detroit with Daddy, is in nine-year-old trouble in this one, and it seems worse because Mother's away with Cathy for the weekend, the very weekend when Detroit friend Mary Ellen comes to visit. Of course Chris must take Mary Ellen to see her school on Saturday, of course they must go in when they find the door open, of course they must play school in the empty classroom with their dolls. . . until the noon whistle sounds and they discover that they are locked in; Chris' ingenuity and the providential appearance of classmate Walter get them out but they leave the dolls behind. How Chris copes with this problem, in between lesser dilemmas like a fire in a restaurant and a friendly dog in a pool, gives the story a sustaining urgency (though purists might wish she'd confessed without pressure). The message is that Chris does cope, consistently, and little girls will eagerly identify.