Percy and his mother decide to go to Montauk for the weekend, hoping to escape all of the craziness that has occurred back in New York City. Percy takes part in a game of basketball but is frustrated when he keeps accidentally injuring his teammates. He learns some interesting things about himself and his newfound powers by the end of the game.
Back at the hotel, a three-headed dog burst into Percy's hotel room and attacks his mother. Grover steps forward and shows that he is a satyr, a half-human, half-goat creature. Grover was Percy's protector. He took Percy to his mother and then teleported them both to a bus station.
At the bus station, Percy encounters a woman who calls herself Mrs. Dodds in the restroom. She turns into a fury and attacks Percy. Grover helps him escape by leading the fury away from him and then they board a bus. On the bus, Grover informs Percy that he is a demigod, a child of a Greek god or goddess. He states that Percy must travel to Camp Half-Blood, a summer camp for demigods, to protect himself and find answers to his many confusing questions.