The tale of Arcadia unfolds with Basilius, the esteemed duke, who encounters a surprising prophecy that changes the course of his tranquil reign. His family—wife Gynecia and daughters Pamela and Philoclea—are at the heart of this prophecy that foretells upheaval and personal betrayal. Determined to thwart fate, Basilius retreats into isolation, setting off a chain of unexpected events.

The Oracle’s Prophecy and Basilius’s Response

In his quest for foresight, Basilius consults the Oracle at Delphos, only to hear unsettling predictions: Pamela will be abducted, Philoclea will engage in an inappropriate romance, Gynecia will stray, and a foreigner will seize his throne. Faced with this ominous forecast, Basilius confides in his loyal friend Philanax, entrusting him with governance as he escapes with his family into seclusion. Basilius occupies one lodge with Gynecia and Philoclea, while Pamela is placed under the watchful eye of the honest shepherd Dametas.

The Arrival of Pyrocles and Musidorus

Amidst this retreat, two noble princes, Pyrocles and Musidorus, find themselves in Arcadia after surviving a shipwreck and numerous daring escapades. Pyrocles is captivated by Philoclea upon seeing her portrait. Enamored, he devises a plan to meet her by disguising himself as an Amazon named Zelmane, despite Musidorus’s attempts to dissuade him from such folly.

Encounter and Deception

Determined, Pyrocles, disguised as Zelmane, approaches the duke’s lodges, while Musidorus remains nearby. Zelmane’s arrival is reported by Dametas, prompting Basilius, who is unknowingly enchanted by Zelmane, to invite "her" into his circle. Meanwhile, Musidorus, under the guise of a shepherd named Dorus, gains employment with Dametas, thus establishing proximity to Pamela, with whom he is smitten.

The Unfolding Romantic Entanglements

Heroics ensue as Zelmane saves Philoclea from a lion, inadvertently revealing to Gynecia that "she" is a man, sparking Gynecia’s own affections. Similarly, Dorus rescues Pamela from a bear, deepening their bond. The Arcadian pastoral gatherings, rich in song and dance, further weave the intricate tapestry of love between the disguised nobles and the duke’s daughters.

Complexities of Love and Identity

During a pastoral festival, both Basilius and Gynecia confess their love for Zelmane, complicating Philoclea’s emotions. Meanwhile, Dorus feigns affection for Mopsa to be near Pamela, subtly communicating his true feelings through tales and verse. Tensions rise as Pyrocles reveals his true identity to Philoclea, causing a tumult of emotions, while Gynecia’s jealousy grows unchecked.

Rising Conflict and Revelations

As unrest brews among the Arcadian villagers over Basilius’s negligence, Pyrocles eloquently quells their dissent, reaffirming loyalty to the duke. This victory reignites the fervor of festival and debate, contrasting reason against passion. Dorus, yearning for Pamela’s company, proposes escape to Thessalia, while Pyrocles seeks to end the advances of Basilius and Gynecia by offering ambiguous reassurances.

Clandestine Meetings and Escape

Dorus cleverly orchestrates Pamela’s escape, but they are soon besieged by bandits. Meanwhile, Pyrocles, under pressure from Gynecia’s advances, feigns reciprocation, causing Philoclea deep distress. To create a private meeting place with Philoclea, Pyrocles relocates to a nearby cave, setting clandestine appointments with both Basilius and Gynecia.

Unveiling Truth and Resolution

In the cave, Basilius inadvertently meets his disguised wife Gynecia, leading to mutual recognition and repentance. Simultaneously, Pyrocles, revealing himself to Philoclea, wins her heart in a secret rendezvous. The betrayal is uncovered by Dametas, who alerts the villagers, prompting a surge of emotions and guilt admissions, particularly from Gynecia.

Trial and Redemption

Chaos reigns as accusations fly regarding the duke’s apparent demise, and Evarchus, king of Macedon, is called to judge the implicated parties. Though Gynecia pleads for execution, Evarchus, unaware of the princes’ identities, initially condemns them to death. The misunderstanding is resolved when Basilius awakens from his potion-induced slumber, leading to forgiveness and reconciliation.

A Prophecy Fulfilled

Ultimately, the Oracle’s prophecy comes to pass in unexpected ways, resulting in joy rather than tragedy. With truth and love restored, the young lovers marry, each ascending to the roles befitting their noble heritage. In reflection, Basilius marvels at how destiny unfolds, bringing peace and prosperity back to Arcadia.