Summary
Percy thinks everything is going to be perfect. He's got his memories back, he's preator of New Rome, his girlfriend is back, and the Romans are treating them normally. But then the Greek warship, Argo 2, fires at New Rome. After a lot of confusion and fighting Romans they fled but not without the ship getting damaged. They find out it was Leo who fired against New Rome. With Piper's visions they stopped at a place nearby and met Bacchus, wine wine god, who gave them advice but soon fled realizing he was in a trap. Then Percy and Jason get possessed by Gaea's evil wind spirits and the spirits force Percy and Jason to fight each other. Piper soon breaks up the fight but both Percy and Jason were knocked out. They were taken back to the ship. Meanwhile, Leo and Hazel went to search for gold and other items essential for repair of the ship. Where they found Nemesis, the goddess of revenge, and got lead off to fight nymphs and Narcissus. After running back they take off and leave to Atlanta. On they way there Piper uses her charm-speaking ability to make the Eidolons, the spirits that had possessed Leo, Jason, and Percy. There they were to meet Phorcys and Keto. Eventually Percy, Frank and Coach Hedge fight them off. And from the information they received from Phorcys they left for Charleston. Annabeth, Piper, and Hazel go to Battery Park to find a mysterious ghost, which happened to be Aphrodite. Aphrodite tells them about their love lives and the other Olympians that are suffering from being confused about their Roman or Greek identity. After their talk, the angry Romans come, and war breaks out. Annabeth meets Reyna in Fort Sumter who was there to retrieve a map which will save her friends. Reyna begs Annabeth to come with her and die a painful death to save her camp, but Annabeth tells Reyna that she will only follow the mark. The seven reach the ship and leave safely to go to Chiron's brothers, who live in the sea. During the trip they get attacked by a huge shrimp-like monster. Leo, Frank, and Hazel go underwater and find the icthyocentaurs, Chiron's brothers. After coming back and hearing their stories the seven speed off to Rome. . They meet Hercules near the pillars, or the entrance to Rome, and Piper and Jason get the second horn of Achelous, the bull-headed river god. Even though it was Hercules who ordered them to cut it off, Piper decided that Hercules did not deserve the horn and keeps it for herself. She brings forth a pile of supplies, and Hercules gets trapped in the supplies. The seven demigods then cross the pillars and sail into Rome. Annabeth has to find the Athena Parthenos by following the Mark of Athena and battle its guardian Arachne. Percy, Jason, and Piper travel into an underground area beneath the Colosseum and battle the twin giants, Otis and Ephialtes, the anti-Dionysus. Frank, Hazel, and Leo travel in search of Nico, and find Archimedes' scrolls on spheres.Eventually Annabeth outsmarts Arachne by tricking her into weaving her own trap. Percy and Jason battle the giants and with help from Bacchus and they rescue Nico. Frank, Hazel, and Leo battle the Eidolons and rescue Archimedes' scrolls. They all meet up where Annabeth secures the Athena Parthenos. However, Annabeth leg gets stuck onto one of Aranche's webs and Arachne trys to pull her into Tartarus. Percy manages to grab a hold of Annabeth, but soon realizes he will follow down with her if he doesn't let go of her. Despite Annabeth screaming at him to let her go, Percy refuses to leave her again and the two fall into the darkness. However before falling, Percy told Nico to lead the demigods to the Doors of Death, while he and Annabeth could meet them at the end of Tartarus on the Doors' other side. Nico and Hazel both say they are fairly sure Percy and Annabeth are not dead yet.