Helen prays before the tomb of Proteus, late king of Egypt, who protects her from any dishonor while her husband Menelaus leads the Greek hosts at the siege of Troy. Menelaus mistakenly believes that Helen has been carried off to Troy by Paris, the son of the Trojan king. Helen recalls that three goddesses, Hera, Cypris (Aphrodite), and Athena appeared before Paris and asked him to judge which was the fairest. Cypris promised him Helen as a prize for choosing her, but Hera, enraged at being rejected, caused a phantom Helen to be carried off to Troy in place of the real one. Thus, in Egypt, the real Helen prays for the safety of her husband and for protection against Theoclymenus, son of Proteus, who is determined to marry her.

Helen is accosted by Teucer, an exile from Achaea, who brings tidings of the end of the war: The Greeks seeking their homelands have been ruined; Menelaus and Helen have disappeared; and Leda, Helen’s mother, has killed herself because she could not endure her daughter’s shame. The anguished Helen then warns Teucer not to seek out the prophet Theonoe, as he intends, but to flee, for any Greek found in Egypt will be killed. The chorus grieves for Helen, who laments her miserable fate and threatens suicide. In despair, she takes the advice of the chorus and herself seeks out Theonoe.

Menelaus, shipwrecked and in rags, appears before the palace seeking aid, only to be berated and sent off by a portress who warns him that since Theoclymenus has Helen in his possession no Greeks are welcome in Egypt. Menelaus is astounded, for he has just left his Helen secure in a nearby cave. As he stands there in bewilderment, Helen emerges from her conference with Theonoe and confronts the amazed Menelaus. Helen cannot convince him that she is indeed his wife until a messenger brings word to Menelaus that the Helen he left at the cave is gone, having soared away into the air. The long-separated lovers then embrace, rejoice, and tell each other of all the adventures that have befallen them. Their immense happiness is darkened by the realization of their present plight: Theoclymenus is determined to make Helen his own, and Menelaus is in danger of his life. The two resolve that if they cannot concoct some scheme for escape, they will commit suicide rather than be separated again.

Theonoe, aware of the presence of Menelaus, appears to inform him that, although Hera has relented and is now willing to let him return to Sparta with Helen, Cypris is unwilling to have it revealed that she bribed Paris to be chosen as the most beautiful of the goddesses. Therefore Theonoe, serving Cypris, feels obliged to expose Menelaus to her brother. Terrified, Helen falls to her knees in tears and supplication, and the enraged Menelaus threatens that they would die rather than submit. Theonoe relents, promises to keep silent, and urges them to devise some means of escape.

After rejecting several of Menelaus’ desperate proposals, Helen hits upon a scheme that she puts into operation as soon as Theoclymenus returns from a hunting trip. Appearing before him in mourning clothes and addressing him for the first time as her lord, Helen tells him in a pitiful voice that a shipwrecked Greek warrior has just brought her word that Menelaus has drowned at sea. She is now ready, she adds, to marry Theoclymenus if he will permit proper burial honors, in the Greek fashion, for her husband. Theoclymenus consents and turns to Menelaus, who is posing as the bearer of the sad tidings, for instructions concerning Greek burial rites for a king drowned at sea. Menelaus informs him that there must be a blood offering, an empty bier decked and carried in procession, bronze arms, and a supply of the fruits of the earth, all to be taken out to sea in a large ship from which the widow must commit everything to the waters. The gullible Theoclymenus, anxious to foster piety in the woman who is about to become his wife, agrees to everything, and preparations are made for both a funeral and a royal wedding.

Later, a breathless messenger comes running to Theoclymenus with the news that Helen has escaped with Menelaus. He describes in detail how the Greek stranger commanding the ship permitted a large number of shipwrecked sailors to come aboard and how, when the time came to slay the bull, the stranger, instead of uttering a funeral prayer, called upon Poseidon to allow him and his wife to sail safely to Sparta. The aroused Egyptians sought to turn back the ship, but they were slaughtered by the Greek warriors whom Menelaus had smuggled aboard. Theoclymenus, enraged, realizes that pursuit is hopeless but resolves to avenge himself on his treacherous sister, Theonoe. A servant from the palace tries in vain to convince him that he ought to accept events as they have happened. Both the servant and Theonoe are saved from death when the Dioscuri, the twin sons of Zeus, appear from the sky to restrain Theoclymenus’ rage and explain to him that Heaven has ordained the return of Helen and Menelaus to their homeland. Theoclymenus is chastened, and the chorus chants familiar lines about the irony of fate.