Angelica, unable to forget Rinaldo since she has partaken of the waters of love, now induces the magician Malgigi to entice her beloved to an island over which she reigns, where she vainly tries to win his affections and to detain him by her side. Still under the influence of the waters of hate, Rinaldo escapes, only to land in a gloomy country, where he is plunged into a loathsome den. There a monster is about to devour him, when Angelica comes to his rescue. But, even though she saves his life, he ungratefully refuses to return her affection, and abruptly leaves her to encounter other untoward adventures. Meantime Orlando, still searching for Angelica, encounters a sorceress who gives him a magic draught which causes him to forget the past, and detains him a captive in the island of Dragontine.
Meanwhile the many knights enamoured with Angelica have gone to besiege her father's capital, but while they are thus employed she escapes from the city—thanks to her magic ring—and goes to deliver Orlando. In return, he pledges himself to drive the besiegers away and save her father's capital, and on the way thither encounters Rinaldo, with whom, not knowing who he is, he fights two days, so equally are they matched in strength and skill. The moment comes, however, when Orlando is on the point of slaying Rinaldo, and refrains only because Angelica opportunely reveals his opponent's name.
Still urged by Angelica, Orlando next hastens off to destroy the magic island and free its captives, who hurry back to France while their rescuer journeys to Cathay. There Angelica pretends she has fallen in love with him, and accompanies him when he returns to France under pretext of becoming a Christian. Their way again lies through the forest of Arden, where this time Angelica drinks from the fountain of hatred. All her former love for Rinaldo therefore vanishes, and, as the latter has at the same time partaken of the water of love, their parts are reversed, for it is he who now pursues Angelica whom he previously loathed. His attentions so incense Orlando that he begins a fight, which Charlemagne checks, declaring that Angelica—who is placed in charge of Duke Namus—shall be awarded to the warrior who distinguishes himself most in the coming war.
In the course of this campaign these two knights meet with many adventures, and are accompanied by Bradamant—Rinaldo's sister—who manfully fights by their side. Among their opponents the most formidable are Rogero and the pagan Rodomont, whose boastful language has given rise to the term rodomontade. During one of their encounters, Rogero discovers that his antagonist is Bradamant—a woman—and falls desperately in love with her.
It is at this point that Boiardo's poem ends; and Ariosto, adopting his characters, immediately begins weaving three principal strands of narrative,—one relating to the wars of Charlemagne, another to Orlando's madness, and the third to the love of Rogero and Bradamant,—Rogero, an ancestor of the Ferrara family (Ariosto's patrons), being the real hero of his poem.
Not satisfied at being placed under the care of Duke Namus of Bavaria, Angelica escapes from his guardianship, only to be pursued by the unwelcome attentions of Rinaldo and Ferrau. While these two fight for her possession, the lady, who spends her time fleeing from unwelcome suitors, escapes, only to fall into the hands of Sacripant, King of Circassia, another admirer, who bears her off in triumph. They meet a knight in white armor (Bradamant in quest of Rogero), ere they are overtaken by Rinaldo. A new duel now ensues, this time between Rinaldo and Sacripant, during which Angelica runs away and seeks refuge with a hermit-magician, who then informs the combatants Angelica has been carried off to Paris by Orlando. Hearing this, the rivals cease fighting and join forces to rescue the lady, but, when they arrive in Paris, Charlemagne despatches Rinaldo to England and Scotland, where, among other marvellous adventures, is told the lengthy and fantastic yet beautiful story of Ginevra.
It seems that, although loved by the Duke of Albany, this lady prefers the knight Ariolant. She thereby so enrages her noble suitor that he finally bribes her maid to personate her and admit him by night to her chamber by means of a rope ladder. With fiendish cunning he has advised Ariolant to watch Ginevra, so this true lover, witnessing what he considers irrefutable proof of his lady-love's unchastity, departs in despair to commit suicide. His brother, deeming him already dead, denounces Ginevra, who, brought before the judges, is sentenced to die unless some champion will vindicate her honor. Having meantime discovered the truth, Rinaldo clears the lady by winning a brilliant victory, and leaves only after she is safely married to the man she loves, who after all has not taken his life.
The poet now picks up another thread and shows us Bradamant seeking Rogero, and discovering, by means of Angelica's magic ring, that he is captive of a magician. After a narrow escape, and a vision of the feats her descendants will perform, Bradamant helps Rogero to escape. Soon after, this reckless man vaults upon a hippogriff which lands him on an island, where an enchantress changes her visitors into beasts, stones, trees, etc. Instead of becoming one of her permanent victims, Rogero, warned by the myrtle to which he ties his steed, prevails upon her to release her captives, and after many adventures is borne by the same hippogriff to the island of Ebuda, where a maiden is daily sacrificed to a cannibal Orc. When Rogero discovers that the present victim is Angelica, he promptly delivers her and conveys her to Brittany.
Meantime Orlando, mad with love, is vainly seeking Angelica. He too visits Ebuda—but too late to meet her there—and delivers another maiden. Then he returns to France to find Charlemagne so sorely pressed by foes, that he has implored St. Michael to interfere in his behalf. This archangel, cleverly enlisting the services of Silence and Discord, brings back Rinaldo and other knights, who drive away the disintegrating pagan force after sundry bloody encounters. After one of these, Angelica finds a wounded man, whom she nurses back to health, and marries after a romantic courtship in the course of which they carve their names on many a tree.
Still seeking Angelica, Orlando in due time discovers these names, and on learning Angelica is married becomes violently insane. Discarding his armor,—which another knight piously collects and hangs on a tree with an inscription warning no one to venture to touch it,—Orlando roams hither and thither, performing countless feats of valor, and even swimming across the Strait of Gibraltar to seek adventures in Africa since he cannot get enough in Europe. In the course of his wanderings, Orlando (as well as sundry other characters in the poem) is favored by an apparition of Fata Morgana, the water-fairy, who vainly tries to lure him away from his allegiance to his lady-love by offering him untold treasures.