On the island of Delos, Diana and her nymphs are preparing to celebrate Apollo’s festival day. They hear cries from the sea, where Orione and his companion Filotero are struggling, exhausted, to reach the shore. Diana, horrified at the prospect, sends the swimmers to another part of the island and castigates her nymphs for their prurient curiosity.

Vulcan, with his two Cyclops henchmen, is making his way back to his forge, where much work awaits. No holiday for them. Amore enters in urgent need of more arrows.

Filotero and Orione come ashore, and we learn why the blind Orione has come to Delos to have his sight restored. They hear the forge, and in trepidation, Orione approaches to ask Vulcan for his help. But it is Amore who promises to take Orione to Apollo’s temple and perform the miracle himself.

Venus, hating and hated by Apollo, is not allowed on Delos for his festival. Curiosity, however, has got the better of her, and disguised as an old hag, she has come to see and, if possible, disrupt the festivities. Almost the first thing she sees is her son, Amore, in Apollo’s temple, dispensing miracles to Orione who now sees again.

Venus waylays Amore and angrily reveals herself. He declares that it was all part of his greater plan to upset the day, and his mother is appeased.

Filotero urges Orione to leave Delos now that he has his sight again. He will not; in any case, he is much too tired to make up his mind about anything and must sleep. Filotero concurs in this.

The festivities begin with Diana, Aurora and their nymphs. Amore looks on and, when the two sleeping men are discovered, shoots arrows into Diana and Aurora, who both immediately fall in love with Orione.

Venus is enjoying her day of disguise and is still more delighted when Amore comes to tell her what he has done.

Filotero, pursued by one of Diana’s nymphs, is anxious to leave Delos. Orione, who is faring better and gaining confidence, is inclined to stay. They hide as Titone, with one of Aurora’s nymphs, complains of his wife, of Aurora’s behavior and of his jealous anger at Orione.

Diana then enters with Apollo, trying to disguise her feelings for Orione by dissembling outrage that her brother should accuse her of such weakness.

Venus believes her plan to disrupt things is going awry. Diana, it seems, is enjoying her new sensations of love: “Orione must depart or perish:’ This last conclusion is overheard by our two heroes, who are naturally frightened. They consult the “old hag;’ who says she can summon up a dolphin to take them away. They readily agree, but just as Filotero is about to step onto its back, he disappears, and a rock rises in his place. Venus vanishes, and Orione is left beseeching Nettuno to restore his friend. Fortunately, he does, and they set off in search of the old woman, whom they now think is a witch.

Aurora, alone, laments the jealousy that love has brought her.

Diana, too, is tom between her duty as a goddess and her new love for Orione, whom she now encounters. They declare their love, but in spite of his importuning, she, for fear of discovery by the other gods, begs him to keep apart and silent until such time as they can be openly together. In his frustration, he cries out, ‘1 care naught for Apollo and still less for Aurora.”

Aurora, with Titone, hears this and offers it as proof of her innocence and constancy. Amore joins them and indignantly brings news that Orione has challenged the gods to a swimming race. Apollo enters, angry with Amore for making his sister fall in love. They unite in their intention to be revenged on Orione and warn us of the snares of love.

Orione cannot bear to leave Diana, and even when Filotero warns him of the danger, he says he will stay and outface the gods, who overhear him and are confirmed in their intention of revenge.

Venus gets caught by Vulcan and his henchmen, and only by telling unpalatable truths does she manage to escape.

Diana waits for Orione but Apollo arrives and taunts her with her weakened bow arm. She, in her anger, agrees to shoot a monster swimming far out to sea. She does, her bow shatters, and she slowly realizes she has been tricked into killing Orione.

Down on the shore, Filotero waits for Orione to finish his race and philosophizes on the disappointment that so often follows the expectation of waiting.

Diana’s nymph tells him the sad news of Orione’s death, and they go off to find the body and encounter the grief-stricken Diana.

Nettuno rises from the sea, threatening to call up the winds and storms so as to destroy Delos and the gods for killing his son.

Disaster is averted by the arrival of Giove, who placates everyone by saying that it all came about by decree of Destiny and that Orione shall take his place as a constellation in the night sky.