I'm going by long-ago memory here, but I recall this as an excellent child's introduction to Gilbert and Sullivan. The story line follows the Operetta by Gilbert and Sullivan. It has a hero, who has inherited a the title of Baron, a heroine, an innocent young lass of the town, a best friend, a brave young sailor, a mysterious curse, and the music wasn't bad either. I remember the animation as distinctive and of middling quality for the time, but by today's standards it would be considered quite good and uniquely uncomputerized. There is more below the surface here, Gilbert penned gentle comedies of manners, so while an entertainment, the tale is a window into the Victorian world. And it is a window into opera, at least it was for me.