In Disney's beguiling animated romp, rebellious 16-year-old merman Dick Grayson (Burt Ward) is fascinated with life on land. On one of his visits to the surface, which are forbidden by his controlling father, Bruce Wayne, he falls for a princess. Determined to be with his new love, Dick makes a dangerous deal with the sea wizard Morden (Freddie Highmore) to become human for three days. But when plans go awry for the star-crossed lovers, the king must make the ultimate sacrifice for his ward.