The three nymphs, Britomarte, Clizia and Cloe, observe Doristo resting. After they leave, Amore (Cupid) wakes him, and then hides. Doristo is startled to find himself by a large tree that grows golden apples. When he tries to pick one, Amore intercedes and explains they are on the island of Cintia, and the garden belongs to Diana, goddess of the hunt and of the virtuous. She soon appears with her three nymphs, and it becomes clear that the tree is a symbol of chastity, and an enemy of carnal love – if anyone should stray, they are pelted with the gilded fruit. Doristo has been selected to help Amore restore the natural order of the human condition to this island. Accordingly, the shepherd lustfully admires the beauty of the women, and Diana is affronted, turning him into a sapling. The ladies depart.
Silvio pursues Endimione out of the forest, intent on harming him. Amore re-enters and both men suddenly stop in their tracks. They sort out their dispute – Endimione has slain Silvio’s greyhound, which has been terrorizing his sheep. Amore offers to restore the dog’s life if Silvio will cut the sapling down. Doristo is restored to his original form, slightly injured, and tells his story – he was kidnapped from his home and awoke on the island. The three men consider their options for escape.
The nymphs return, and admire the fair youths, but realize any flirtation will bring on the wrath of Diana. Nonetheless, they make a plan to overcome the men’s resolve. They hide the men in a cave as the goddess approaches. Diana encounters Amore, still disguised as a messenger. He makes a case for the nymphs to experience true love, touting the merits of strong emotion. Diana chastises him for his audacity and departs in a rage.
The men contemplate their next move as Amore slyly offers his darts to aid in their seductions. Diana returns, now armed with her resolute nymphs to rid the garden of the nefarious men by threatening to harm them. Endimione pacifies the goddess, leaving her both angry and confused, thus satisfying the first stage of Amore’s clever machinations.
As Britomarte contemplates an escape along with her male companions, the goddess soon discovers the plot and begins to mete out her fabled wrath at the wayward nymph, but is suddenly moved by something foreign in her heart. After she retires, Amore reappears and ushers Silvio, Doristo, and Britomarte away. Only Endimione remains behind, professing his love for Diana when she returns with Cloe and Clizia. Although still enraged, the goddess is unable to exact vengeance for the disruption of her chaste garden. She commands her remaining nymphs to do the work for her, but they cannot perform the deed.
Silvio returns and both men are distressed to find an escape from the island. Amore observes undetected, enjoying the tumultuous situation with glee. Elsewhere, Doristo awaits the errant Britomarte. He professes his everlasting affection, but they are interrupted by Amore, Endimione, Silvio, Clizia, and Cloe. Meanwhile, Diana searches for the intrusive party. She happens upon a slumbering Endimione. Her heart is melted by his apparent innocence, and upon waking, his tender entreaties. Amore suggests Silvio pose as the temple priest, while the three nymphs admire Doristo, each vying for his attention, and then threatening to punish him for his lack of fidelity. Diana is torn between her requisite divine duties and her desire for a flesh-and-blood man.