Theseus, Hippolytus, and Theramenes appear, and Theseus goes eagerly toward his wife, but she refuses his embrace, saying she is no longer worthy of it, and flees. Troubled, Theseus asks Hippolytus the meaning of this strange welcome. Hippolytus, embarrassed, suggests that Theseus ask Phaedra to explain; for his part, he also has a request to make. He can no longer live in the same place with his father's wife, and he wants his father's permission to leave Troezen.
Theseus protests, but Hippolytus reminds him that at his age, Theseus had already killed more than one monster and traveled strange lands, but Hippolytus has not yet equaled even the exploits of his mother, much less those of his father. "Permit me," he begs, "if there is still some monster which has escaped you, to bring you the trophy of his death, or to die honorably in the attempt."
Theseus is dismayed. What kind of welcome is this for a returning husband and father? He might better have remained in prison in Epirus. And he goes on to recount how, out of old friendship, he consented to help Pirithous carry off the wife of the tyrant of Epirus, how that tyrant captured them both, fed Pirithous to the monsters, and imprisoned Theseus in a cave. Fortunately, Theseus was able to trick his enemy and throw him as food to his own monsters. Once free, his only thought was to rejoin his loved ones, wife and son, but now both reject him, both wish to leave him. What is going on? Who has betrayed him? Hippolytus is silent, and, deeply hurt, Theseus cries, "Is my own son cooperating with my enemies?" Phaedra must speak; he will know the truth and learn exactly what is the crime and who the guilty one.
Left alone with Theramenés, Hippolytus too is troubled. Will Phaedra tell the truth, a truth which will certainly cost her her life? What will Theseus say, particularly when he learns that during his absence his son has spoken of love to Aricia, a woman to whom he has forbidden marriage? He fears what is to come, but after all, he is innocent, and innocence has nothing to fear. Perhaps by a skillful approach he can touch his father's heart and win his consent to a love which he will never abandon, no matter what Theseus' reaction is.
No doubt the sudden appearance of Theseus speeds the play to its tragic conclusion. Racine treats with great suppleness what might otherwise have been a contrived plot device. We have already noted that the audience has been prepared for Theseus' entrance. His absence is plausibly explained by a long imprisonment. His violent personality and his past exploits justify his subsequent, merciless severity toward his son. Above all, he is more than a wooden puppet brought in merely to accelerate Phaedra's moral ruin. He has his own tragic interest — a lonely figure, bewildered and exasperated by hints of betrayal and by the strange welcome his family gives him.
At the end of Act III, Racine prepares but does not consummate the final catastrophe. He wants to prolong and intensify the feeling of dread and suspense. Phaedra, by her own ambiguities, has prepared the ground for Oenone's perfidious accusations. Hippolytus unwittingly seals his own doom with his attempt to avoid his father after the latter's long absence. The act ends in a mood of ominous uncertainty as Theseus vows to solve the mystery and Hippolytus muses anxiously about Phaedra's strange behavior, the king's anger, and his own secret, inadmissible love.