Young J.J. (T.J. Hargrave) is a restless Manhattan orphan who tires of life in bleak foster homes and takes off for Central Park, along with his younger sister, Laurie (Lisa Richard). The two begin residing in an old tree house, hiding out and enjoying their adult-free existence. Eventually, J.J. and Laurie form a friendship with another park regular, the elderly Mrs. Miller (Ruth Gordon), who gradually wins their trust and shows the siblings that not all adults are bad.