I'm thinking of starting with a classic "King hires young hero to rescue his kidnapped daughter" story, which ends with the protagonist about to slay the antagonist. As he's about to save the day, the princess releases herself and saves the bad guy. The hero asks if it's some sort of mind control potion, to which the princess replies "I concocted the whole plan. Lord [whatever his name is] works for me. With my father's greatest hero out of the way, we'll conquer the kingdom and run things my way!" You may be wondering why the princess wouldn't just wait for her father to die, but that's to be revealed in the story proper. But have you seen ever seen the abductee turning out to be the mastermind before?