Deadly Doubles — Carolyn Keene

Nancy plays a new kind of sport-- and murder is the name of the game

Nancy and her friends George and Bess fly down to Washington, D.C., to watch some of the world's best tennis players shoot for a championship. But the action is hotter off the court when Nancy gets tangled in a bizarre case of mistaken identity.

Nancy bears a striking resemblance to Teresa Montenegro, the rising young star from San Carlos. Then Teresa's boyfriend is kidnapped, and Teresa may be next! In a last, desperate move to outwit the hired guns, Nancy and Teresa trade places. Nancy strides onto center court to play a deadly game of doubles--while a ruthless killer stalks her from the stands.