Cantos IV, V, VI
Daughter of King of Scotland, Sister of Zerbino, Lover of Ariodantes
TL;DR Chaste Lover Falsely Accused By Spurned Suitor, Saved By Heartbroken Lover
Genevra enters the poem as a damsel in distress whose back-story is related to Rinaldo first by monks and then by her handmaiden. In the process of saving her Rinaldo unravels the mystery of how she came to be falsely accused of the crime of fornication, exposes the villain, and brings a just conclusion to the unhappy events. What follows is full of spoilers.
Genevra is the happy daughter of the King of Scotland and the most beautiful of the women of that land. Amidst the countless suitors for her hand in marriage, her true love is the brave knight of Italy, Ariodantes. Through feats of knightly courage he rises in favor with the king and a marriage to Genevra seems inevitable.
Unfortunately one of Genevra’s spurned suitors, the powerful Duke Polinesso of Albany, cannot accept her rejection and grows to hate both the princess and her true love. Polinesso enlists the aid of his lover Dalinda, handmaiden to Genevra, to destroy their love and ruin their lives.
He arranges for Ariodantes to see him seducing Dalinda, but since Dalinda is dressed up as Genevra, Ariodantes believes that his true love is actually a faithless harlot. In despair, Ariodantes wanders off and throws himself into the sea. All of Scotland, including Genevra, mourn his death.
His brother Lurcanio also sees the set-up scene and, similarly hoodwinked, decides to get justice for his brother by publicly accusing Genevra of breaking Scotland’s fornication law. The king decrees that Genevra will burn at the stake in one month’s time unless a champion arrives to defeat Lurcanio in single combat. The only knight in all of Scotland who has a chance to defeat Lurcanio is Genevra’s brother Zerbino, but he is off questing in Europe.
Rinaldo, having learned the sordid tale from Dalinda herself, arrives in St. Andrews to expose Polinesso and put a stop to the execution. To everyone’s surprise, a black knight has gotten there first and is already fighting Lurcanio to save Genevra.
Rinaldo interrupts the duel, shares Dalinda’s testimony, and kills Polinesso in single combat to uphold his claim. The black knight reveals himself to be Ariodantes, not dead after all and still loving Genevra too much to let her die. All is forgiven, the king gives him Albany’s title and lands, and they all live happily ever after.