Ruddigore is a parody of the stock melodrama—the villain who carries off the maiden; the priggishly good-mannered poor-but-virtuous-heroine; the hero in disguise, and his faithful old retainer who dreams of their former glory days; the snake in the grass who claims to be following his heart; the wild, mad girl; the swagger of fire-eating patriotism; ghosts coming to life to enforce a curse; and so forth. But as one critic noted, Gilbert turns the moral absolutes of melodrama upside down: Good becomes bad, bad becomes good, and heroes take the easy way out.

None of the village girls stand a chance at marriage, because all the young men of the village love Rose Maybud, but do not measure up to her strict etiquette. Robin Oakapple also loves Rose, but he is too shy to court her. This is partly because he is the accursed Baronet of Ruddigore, in disguise. His brother Despard carries out the curse: he must commit one major crime per day or die in agony. Robin's foster brother, Richard, seeking Rose for himself, tells Despard of Robin's deception, and Despard transfers the curse back to Robin. The ghosts of his ancestors step from their picture frames to confront Robin for failing to conscientiously carry out his duty. Robin agrees to execute the curse faithfully but finds a clever solution to the whole problem after all!