Basilius is the powerful duke of Arcadia, a quiet and peaceful province of Greece. He rules his faithful subjects happily and well. Overcome by an ungovernable curiosity to learn what the future holds for his family—Gynecia, his wife, and their beautiful daughters Pamela and Philoclea—he consults the Oracle at Delphos. There he is told that his older daughter, Pamela, will be stolen from him and that his younger daughter will engage in an unsuitable love affair and his wife will commit adultery. Also a foreign ruler will sit upon his throne—all within a year.

Basilius repeats the prophecy to his friend Philanax, whom he has left in charge of the country while he, in an effort to escape the destiny foretold by the Oracle, has taken his wife and daughters into a secluded part of the country to live for the year. Basilius lives in one of two lodges with his wife and Philoclea; in the other, he puts Pamela under the care of Dametas, a rude shepherd of whose honesty Basilius has a high opinion.

Shortly after the duke’s retirement, two young princes, Pyrocles and Musidorus, arrive in Arcadia. Reared together in close friendship, these young men of great courage, personal beauty, and integrity have been swept ashore at Lydia after experiencing a shipwreck and many strange adventures as well as performing many daring and honorable acts.

Pyrocles sees a picture of Philoclea, learns of her enforced retirement, and falls in love with her. Determined to see the princess face-to-face, he tells Musidorus of his love and of his plan to disguise himself as a chivalric Amazon and to approach Philoclea in woman’s guise. For a name, he takes that of his lost lady Zelmane.

After a lengthy debate, in which Musidorus attempts to convince his friend of the folly of love, Pyrocles still remains firm in his intention; and the two princes travel to the place of the duke’s retirement with Pyrocles in his disguise as an Amazon. While Musidorus waits in a nearby wood, Pyrocles, now Zelmane, sits down and sings a melancholy song that awakens Dametas, who hastens to the duke’s lodge to tell him of a strange woman who has arrived in the vicinity.

Basilius, upon seeing Pyrocles in his disguise, falls in love with the supposed Amazon. His true identity still unsuspected, Pyrocles is introduced to the duke’s family and invited to remain with them for a while. Soon, a young shepherd appears. He is Musidorus, who has fallen in love with Pamela on sight and has assumed a disguise of his own. Musidorus, under the name Dorus, is taken by the chief herdsman as a servant after telling his contrived tale of having been sent by a friend to serve Dametas.

Zelmane saves Philoclea from a savage lion, but in doing so, the duke’s wife, Gynecia, discovers him to be a man. She immediately falls in love with him. Dorus, meanwhile, saves Pamela from a bear. Before long, both princesses become enamored of the disguised princes.

The Arcadian shepherds, as is their custom, meet and exchange poetic songs for their own entertainment and that of the duke’s family and his guests. The songs, often accompanied by dancing, chiefly concern the gods and the human passions. This occasion only increases the intensity of the tangle of love relationships that have so rapidly developed.

After the pastoral festival, Gynecia and Basilius both declare their love for Zelmane, and Philoclea is puzzled greatly by the strange passion she feels for the person she has thought a woman. In the meantime, Dorus pretends to be in love with Mopsa, Dametas’s daughter, to be near Pamela, who in this manner becomes aware of his affection for her. He also manages to reveal his true station to her by means of subtle stories and poems.

Pyrocles, distressed by the advances of Basilius, reveals his true identity to Philoclea, who at first embraces him joyously but then becomes ashamed of her sudden show of affection. Gynecia, suspecting this attachment, is overcome with jealousy. While Gynecia, having sent Philoclea home from a meeting with Pyrocles, is starting to tell the disguised prince of the depth of her love, they are attacked by some roving ruffians. With the aid of some shepherds, Pyrocles, Basilius, and then Dorus drive off the attackers.

The citizens of a nearby Arcadian village, meantime, enraged by the duke’s seeming unconcern about his country, rise in protest. In an impassioned speech, Pyrocles convinces them of their error and stirs in them a renewed loyalty to Basilius. This triumph is celebrated by another pastoral entertainment, largely taken up with a poetic debate between Reason and Passion. The poems, dances, and stories increase the depth of the emotions felt by the royal party.

Dorus then tells his friend of his moderate success with Pamela, whom he has urged to flee with him to Thessalia. Pyrocles, sharing Dorus’s sorrow over their separation, decides to press his suit of Philoclea and to rid himself of the importunate demands of Basilius and Gynecia. When they renew their entreaties, Pyrocles, still in his disguise and fearing to deny them outright, gives them hopeful but obscure answers.

Meanwhile, Dorus, having tricked Dametas and his family into leaving the lodge, has escaped with Pamela to a forest on the way to Thessalia. There they are attacked by a band of ruffians. The false Zelmane, hard pressed by Gynecia’s declarations, is forced to pretend a deep passion for her, a situation that so distresses Philoclea that she keeps to her room in the lodge in profound sorrow. To be free to execute a plan to be alone with Philoclea, Pyrocles moves from the lodge to a dark cave not far away. He then takes the duke and his wife aside separately and makes an assignation with each at the same time in the cave.

Gynecia, who has dressed like Zelmane, meets Basilius in the cave; she is not recognized by her husband. Ashamed of her actions, she embraces him lovingly. Back at the lodge, Pyrocles, now in his own person, creeps into Philoclea’s room and, after a brief time, wins her over and stays the night.

Dametas, realizing that he has been tricked, begins a search for Pamela. Entering the duke’s lodge by a secret entrance, he discovers Philoclea and Pyrocles asleep. He leaves hastily to inform the local citizens of the treachery. Gynecia, angered at her husband’s praise of Zelmane, reveals her identity in the cave. Basilius, ashamed, repents his weakness, pledges renewed love to his wife, and drinks a long draught from a cup of a mysterious beverage standing close by. The liquid is a potion, believed by Gynecia to be a love philter, which the duchess had brought to give to Zelmane. After drinking it, Basilius falls to the ground and appears to die. After the duke’s death is discovered, Philanax and his troop of soldiers imprison Gynecia, Pyrocles, and Philoclea.

The rogues who had attacked Dorus and Pamela, the remnant of the rebellious band that had earlier caused much trouble, overwhelm the lovers and capture them. While in captivity, Musidorus reveals his actual name and rank. A short time later, some of Philanax’s soldiers are sent to search for Pamela and come upon the band and their prisoners. Recognizing the princess, the soldiers return the entire group to Philanax, who puts the lovers under restraint.

There is now a great turmoil, and many opinions and beliefs are exchanged as to the real guilt in the death of the duke and the disgrace of the princesses. Hearing that Evarchus, the king of Macedon, has arrived in Arcadia to visit the duke, Philanax persuades him to be the judge in the trial of the five people involved. Gynecia admits her guilt and begs to be executed. Then Evarchus, not recognizing his son and his nephew because they have been away for such a long time, condemns the two princes to death and the princesses to milder punishments. Even after learning the true identity of the young men, Evarchus refuses, from a deep sense of justice, to alter his verdict.

At this point Basilius, who had swallowed only a powerful sleeping potion, awakens. The young lovers and the duchess are promptly forgiven. Basilius ponders on how accurately the Oracle’s prophecy has been fulfilled and how happily events have turned out. The princes and their loves soon wed and assume the high stations for which their rank fits them.