a is a prince/princess who has multiple suitors and they'd ignore his suitors every time. one day, they're kidnapped by b, who's an evil sorcerer/sorceress who's jealous of their wealth. they're planning to curse a but, a ends up falling in love with them and they just turned evil themselves, making sure everyone who dares to hurt b shall be tortured and suffer a great pain
whether b falls in love with a or not is up to you