Charles Underhill, a widower, would do anything to protect his young son Jim from the horrors of the playground... a playground which he and the boy pass daily and whose tumult and activity brings back to him the anguish of his own childhood. The playground like childhood itself is a nightmare of torment and vulnerability; his sensitive son, he fears, will be destroyed there just as it almost happened to him, so many years ago. Underhill's sister, Carol - who after his wife's death has moved in to help raise the boy - feels differently: the Playground is preparation for life, Jim will survive the experience and be the better for it, more equipped to deal with the rigor and obligation of adult existence. Underhill, caught between his own fear and his sister's invocation of reason, does not know what to do. A mysterious boy in the playground calls out to him, seems to know all too well why Underhill is there, what the source of Underhill's agony really is. Also lurking is a mysterious Manager to whom this strange boy directs Underhill. An agreement can be made, perhaps, the boy says. Perhaps Jim can be spared the Playground. Of course, a substitute must be found -