A servant arrives with startling news: Theseus is dead. Hippolytus has learned of his father's death from a ship just arrived in port, and Athens is in an uproar. A new ruler must be chosen: Some support the legitimate claim of Phaedra's oldest son, others favor Hippolytus, some even want to put Aricia on the throne.
In the face of this new development, Oenone's view of Phaedra's problem changes. Almost ready to agree that Phaedra must die, she now points out that her queen must live to protect her son. Moreover, Theseus' death puts her in a new position in relation to Hippolytus. Her love for him may be indiscreet, but it is no longer incestuous. Hippolytus has a right to inherit Troezen, but Athens properly belongs to Phaedra's son. Phaedra must see her stepson and persuade him to support her just claim; indeed, it may be desirable for the two to unite to combat Aricia. Reluctantly, Phaedra consents.
The announcement of Theseus' death is one of the rare occasions when Racine uses an external event, rather than a psychological development, to further his plot But this event alone does not create the reversal in Phaedra's attitude; it only adds fuel to the fire. Oenone is the one who really fans the flame. She insidiously reawakens Phaedra's hopes by appealing to her sense of maternal duty, by pointing out that her love is now not entirely illegitimate. The play thus remains essentially a psychological conflict.
Furthermore, the reversal is more apparent than real. The audience is aware of the futility of Oenone's suggestion. It knows the impossibility of a pact between Phaedra and Hippolytus against Aricia, since Hippolytus is in love with the young girl. The news, therefore, adds only a note of dramatic irony and opens the way to an overt manifestation of Phaedra's passion.