When a gang of trouble-making teens asks a very flattered eleven-year-old Harry ChaSe to join in their ""war"" on deserted Thatcher Island, never for a second do you believe this will turn out to be any ordinary child's play. The suspense comes, however, in seeing just how far ""the game"" will go. Under the command of thuggish Doug Morrison, the band of bush-league sadists first traps Harry's younger sister and John, the ""Fresh Air kid"" who's come to spend two weeks with the Chases; then throws them in a sand pit; and finally proceeds to toss lighted matches at their victims. Harry comes to the rescue, but to her credit Degens keeps his motives credibly tarnished. Realizing that the older boys never meant to include him ""on their team,"" Harry--matches in hand--gives Doug a taste of his medicine and in the process sets fire to Thatcher Island. Harry gets home free awfully easily (the Coast Guard quickly puts out the fire and it looks as though Harry's parents will never be the wiser). Of course it would be the New York City slum kid who's the most decent and ""civilized""--and this is altogether more conventional than Transport 7-41-R. But Degens knows how to keep you on the edge of your chair, and her view of children--as canny manipulators of naive, rather obtuse adults--is a fine, jolting turn-around.