Percy admits that he abandons Grover at the bus terminal and takes a taxi home alone. On the way, Percy reflects on his mother, Sally Jackson, whose difficult life and steady kindness make him admire her even more, and on his missing father, whom Sally has always described as rich, important, and lost at sea. Percy also explains how Sally married Gabe Ugliano, a cruel, filthy, bullying stepfather who regularly takes Percy's money and intimidates him into silence.

At the apartment, Gabe is playing poker and immediately demands cash from Percy. Percy gives up his taxi change to avoid a bigger confrontation, then goes to his room, where fear from the bus ride returns and makes him feel as if something is hunting him. Sally arrives home, comforts Percy, and focuses less on his expulsion than on whether he is truly all right. Percy hides the truth about Mrs. Dodds and the old women, but Sally senses he is holding something back.

Sally offers Percy a surprise trip to Montauk, and Percy eagerly agrees because the beach cabin is their special refuge. To make the trip happen, Sally carefully placates Gabe, and Percy swallows his anger long enough to apologize so Gabe will let them take the car. As Percy and Sally leave, Percy makes a strange warding gesture he copied from Grover, and the screen door slams into Gabe hard enough to knock him forward, hinting that Percy may have caused it somehow.

In Montauk, Percy and Sally settle into their old routine, enjoy blue food, and briefly recover some peace. Around the campfire, Percy asks again about his father, and Sally reveals that Percy's father only spent one summer with her and left before Percy was born. When Percy worries about being sent away again, Sally finally admits that Percy has never been safe, that strange threats have followed him since childhood, and that the only remaining option may be a mysterious summer camp Percy's father once wanted him to attend. Sally refuses to explain more because she fears that sending Percy there could mean losing him for good.

That night Percy dreams of a white horse and a golden eagle fighting while a monstrous voice from beneath the earth urges them on. He wakes to a violent storm battering the cabin, and Grover appears at the door in a panic. Sally realizes the danger has arrived and demands the truth from Percy, so Percy finally blurts out what happened with Mrs. Dodds and the Fates. As Sally orders both boys to the car, Percy sees that Grover's disability was a disguise: Grover has goat legs and cloven hooves, confirming that the impossible is real and that something is pursuing them.