Annabeth’s singular focus on the Mark of Athena contributes Percy’s feelings of alienation and uselessness. Making matters worse, since they entered the Mare Nostrum, the Argo has been under constant attack by a variety of mythical monsters. Percy has a nightmare in which Ephialtes and Otis report to a mystery woman that “they” are approaching (261). She hopes the latest of Athena’s children will prove “a worthy victim” (161). Percy notices that the coins glistening in Ephialtes’s hair match Annabeth’s coin from her mother; they are trophies. Ephialtes reminds the mystery woman that Gaea wants Annabeth and Percy alive so that their blood can be spilled “on the ancient stones” (163).

As Percy wakes from his dream, Jason tells him the ship has dropped into the water. It is Percy’s turn to keep watch. Back on deck, he reveals his dream to Annabeth. She tells him not to tell the others, since it will make them worry, and she must go on her mission alone. Percy is angry and does not know how he will be able to let her go, but he understands the importance of her quest. Staring out at sea, he feels its ancient power and significance and realizes that the monsters know the demigods have returned.