In order to try to head off Kronos' approach by sea, Percy and Beckendorf go to blow up his ship, the Princess Andromeda. However, Kronos is not caught off guard, and Beckendorf sacrifices his life to destroy the ship, while Percy dives overboard and is knocked out by Kronos' scythe when battling him on the ship. Percy is awakened by Tyson (a cyclops and Percy's half-brother). He finds that he is in his father Poseidon's underwater palace, which is under siege by the forces of the Titan Oceanus. Percy wants to stay and help fight with his father, but Poseidon sends Percy back to Camp Half-Blood. At Camp Half Blood, they learn about the mission and Silena, Beckendorf's girlfriend, is in tears. At a meeting Percy hears the Great Prophecy for the first time. Then Percy mentions that they have a spy, someone who has been informing the Titans for years, but they put it aside for now. The Ares cabin had a fight with the Apollo cabin, and is so furious that they wish not to fight in the war. Soon after arriving, Percy leaves again with Nico, son of Hades, to find out how he might stand a chance against Kronos when the time comes. After visiting Luke's mother and talking with Hestia (who is the Last Olympian), goddess of the hearth and home, Percy and Nico's aunt. Percy procures a blessing from his mother, descends into the Underworld for the second time. Here, Nico betrays Percy for information on his past, but he helps Percy with the original plan and bathes in the River Styx like Achilles and Luke before him.