 A friendly troll with a magic green thumb grows one flower too many for the queen, whose laws require all trolls to act meanly, be ugly and scare humans whenever possible. As a punishment, he is exiled to a world of concrete, where he should live a life of proper trolldom: Manhattan. But of all places, his pod lands in Central Park, where he feels right at home. He befriends a young brother and sister, out for the day unknown to their parents, and must immediately protect them from the queen s attack. In the process, the boy learns responsibility, and the unpopular queen is overthrown.