Stanley (Dom DeLuise) is a kindhearted, popular troll who can create flowers with a mere touch. When Gnorga (Cloris Leachman), the mean-spirited Queen of the Kingdom of Trolls discovers Stanley's secret, she banishes him to a faraway place where she assumes nothing green can grow - New York City. Taking refuge in Central Park, Stanley befriends two young children, Gus (Phillip Glasser) and his baby sister Rosie (Tawny Sunshine Glover). The three share wonderful adventures until Gnorga decides to let her mischief-making magic loose in the Big Apple.