Creusa enters the stage accompanied by her elderly and nearly blind slave, whom she helps navigate the steps to the sanctuary. The chorus admits to Creusa that Apollo has announced that Xuthus has a son but she does not. Creusa and her slave question the chorus further, and their news of Xuthus having a son with another woman devastates Creusa.

When the chorus shares that the boy is the temple custodian himself, whom Xuthus named Ion, Creusa moans in agony. The slave accompanying her suspects that Xuthus, having sent his bastard son to be raised in secret at the Delphic sanctuary, orchestrated the retrieval of this son by planning a trip to the oracle with his childless wife, aiming to take advantage of her noble Athenian lineage.

Creusa’s slave offers to lay a trap to kill Ion (supposing him to be Xuthus’s illegitimate son). Creusa privately chides herself for expecting to find her abandoned son. She resolves to publicly admit Apollo’s rape of her.

Creusa approaches the temple of Apollo and berates him (in absentia) for raping her in her youth. She also admits to exposing her child in the cave where he raped her.