In order to gain power in Athens, the hero Theseus defeated the Pallantids, the numerous sons of Pallas, and destroyed them except for their sister Aricia. In order to wipe out her tribe for good, Aricia herself is said to remain celibate and childless, in the service of the goddess Diana. Hippolytus, Theseus' son, is also devoted and committed to Diana. At the same time, however, he feels drawn to Aricia, who reciprocates his love. Hippolytus, in turn, is coveted by his stepmother Phaedra, daughter of the Cretan king Minos and sister of Ariadne. While Phaedra, Hippolytos and Aricia are trapped in a dangerous triangular constellation, Theseus, to whom his father, the sea god Neptune, has given three wishes, has descended into the underworld. He hopes to get his friend Perithoos from there, who out of arrogance wanted to rob Pluto's wife Proserpina from Hades in order to be able to lead back to earthly life. During the time of his absence, Theseus gave his wife Phaedra control of the country and its people.
Aricia prepares to dedicate her life to the goddess in the sacred forest of Diana. Hippolytus appears unexpectedly and confesses that he loves her. The high priestess of Diana and her entourage celebrate the power of pure love. The incoming Phaedra tries to force Hippolytus to give his support when Aricias enters the temple. Aricia asks how she can faithfully dedicate her heart to Diana when she does love Hippolytus. Phaedra furiously threatens the destruction of the temple, while the Diana priestesses call for the goddess to prevent this. Diana herself appears, accompanied by thunder and lightning. She supports Hippolytos and Aricia, whom she sees as connected to her in love for one another, but warns Phaedra not to do anything against divine will. Phaedra, left alone,
Before the gates of the underworld open for him, Theseus is confronted by the fury Tisiphone with the horrors that await him there - any hope of escaping Hades is in vain. Brought before Pluto's throne, Theseus asks for Perithus's release and permission to return to the living. Pluto refuses and instead calls on his hellish spirits to prepare cruel tortures for the fallen heroes. Theseus demands death for himself, but the three Fates, who only know about the future, refuse him - he cannot determine his own fate. Theseus now calls his father Neptune to help him leave the underworld again. Supported by the god Mercury, who also prays for Theseus in the name of Neptune, Pluto releases him from Hades.
In the palace, Phaedra accuses the goddess of love, Venus, of being too cruel to her: she seems powerless against her flaming passion for Hippolytus and her desire for him. Hippolytus arrives with the news that Theseus is no longer returning from the underworld. Phaedra tells her stepson that she has no feelings of hatred towards him, whereupon Hippolytos is happy to support Phaedra. He renounces his father's throne in favor of the son of Phaedra and Theseus, who is to rule in future. Mistaking this generosity mistakenly for love, Phaedra is shocked by Hippolytos' announcement that he only wishes to be reunited with Aricia. Outraged by this, Phaedra now openly discovers her love and desire for him. When she noticed Hippolytus' horror, she throws all her passion and anger on him. Theseus, returning to the palace at this moment, is surprised by the situation that presents itself to him. First Phaedra and then Hippolytos leave him without informing him about what really happened. Phaedra's servant Oenone, who wants to protect her mistress, suggests to Theseus that Hippolytus was just about to do violence to Phaedra. Theseus desperately asks Neptune a third time - he may destroy Hippolytus in order to avenge the shame he suffered. God indicates that he will grant this wish. Phaedra's servant Oenone, who wants to protect her mistress, suggests to Theseus that Hippolytus was just about to do violence to Phaedra. Theseus desperately asks Neptune a third time - he may destroy Hippolytus in order to avenge the shame he suffered. God indicates that he will grant this wish. Phaedra's servant Oenone, who wants to protect her mistress, suggests to Theseus that Hippolytus was just about to do violence to Phaedra. Theseus desperately asks Neptune a third time - he may destroy Hippolytus in order to avenge the shame he suffered. God indicates that he will grant this wish.
Hippolytos prepares to go into exile, but is found by Aricia - she has received news of his unexpected departure and is desperate for answers. Hippolytus is unable to reveal the truth, but reaffirms his unbreakable love for her. Hippolyte asks Aricia to flee with him. The couple swears eternal loyalty - the covenant is to be made in front of Diana's face. A hunting party encourages Hippolytos and Aricie to join them when suddenly a sea monster emerges from the sea. Hippolytos takes on the fight with the monster, with an uncertain outcome. When the fog clears, both have disappeared. Phaedra mourns the death of her beloved Hippolytus.
Aricia awakens from her faint. She laments the loss of her Hippolytos, who obviously did not survive the battle with the sea monster. Together with a group of shepherds, she invokes her patron goddess Diana, who descends from heaven to meet her faithful. She announces a new ruler to them who should rule over the people in the forests according to their will. Hippolytus, saved by the gods, returns. He and Aricia are introduced to the supporters of Diana as the new regents. Aricia hears the song of a nightingale - united with Hippolytus she will begin a new life in happiness and harmony.