The morning after Percy Jackson dreams of Annabeth Chase crushed beneath a collapsing weight, Percy tells Grover Underwood. Grover reveals that Zoë Nightshade also had a nightmare and tried to leave camp during the night, claiming Artemis was lost and that the Hunters needed to rescue her. Percy and Grover realize Percy’s dream about Annabeth and Zoë’s fear for Artemis may be connected.

Grover then shows Percy a Hunters of Artemis recruitment brochure found in Annabeth’s backpack. Percy worries that Annabeth may have been considering joining the Hunters, which makes Percy angry and unsettled. Later, Percy goes alone to the Big House attic to ask the Oracle how to save Annabeth, but the Oracle does not respond. While leaving, Percy finds Aphrodite’s scarf from Waterland among the attic trophies and realizes Annabeth kept it, deepening Percy’s confusion about Annabeth’s feelings and choices.

That night, Camp Half-Blood and the Hunters play capture the flag. The Hunters are visibly anxious because of Zoë’s news about Artemis, while the campers are eager to beat them. Thalia Grace and Percy share leadership of the camp team but quickly clash over strategy: Thalia leads the offense, Percy takes defense, and Nico di Angelo is placed with the guards for safety.

During the game, Percy sees the Hunters divided and decides to abandon defense for a chance at their flag. Percy knocks Bianca di Angelo aside, grabs the Hunters’ flag, and nearly reaches the creek, but Zoë Nightshade has already slipped through the campers’ defenses with Camp Half-Blood’s flag. The Hunters win again, and Thalia blames Percy for ruining her own attack on the Hunters’ base.

Percy and Thalia’s argument escalates into a dangerous duel of divine power: Thalia shocks Percy with lightning, and Percy raises the creek against Thalia. Before Percy can strike, the Oracle unexpectedly leaves the attic and appears before everyone. The Oracle addresses Zoë as the seeker, shows a vision of Artemis chained on a barren mountain, and delivers a prophecy sending five west to find the chained goddess, warning that one will be lost, one will withstand the Titan’s curse, and one will die by a parent’s hand.