Red Rover, Red Rover

Lydia joins teenagers from all over the world in a youth orchestra slated for a concert at New York's Lincoln Center. Her week of rehearsals is soon fraught with intriguea 12-year-old Soviet protege, carefully guarded by KGB agents, looks ready to defect. Lydia's friendship with another Soviet boy, Aleksei, begins with an exchange of communist-capitalist insults, then takes a romantic turn. But there's little time for holding hands: a U.S. agent is following Lydia and even her maestro seems to be involved. Hess handles this rather incredible situation with finesse and humor; it's easy to forgive Lydia for ""tossing her chin'' indignantly and saying to the U.S. agent, ``Sloppy, sloppy, Mr. Smith,'' like a B-movie heroine. But the points about East-West and other international misunderstandings are well-made, offering readers a suspenseful and thought-provoking story. Ages 12-up. (December)