Percy leads Piper and Jason deeper underground. They arrive in a large room filled with machines powered by hellhounds running on hamster-style wheels. From the twenty-foot ceilings, live animals are suspended in cages. Weapons and armor travel along conveyor belts. In his bronze jar, Nico is curled up, sleeping or dead. The demigods are in a hypogeum, the room under a coliseum that holds “set pieces and machinery used to create special effects” (375). Ephialtes and Otis emerge, and Ephialtes explains that they have planned “the greatest spectacle Rome has ever seen—and the last!” (375).

To stall for time, Percy gets Ephialtes talking and learns that Annabeth is on the brink of death, and Hazel, Frank, and Leo are trapped. The giants plan to use Percy, Piper, and Jason for their show. Their destruction of Rome will take one month, until Gaea awakes on August first, “the best date to destroy all humanity” (377). Ephialtes shares the horrors he has planned, unmoved by Percy’s suggestions and Piper’s charmspeak. The three demigods decide to charge the giants.