It is Christmas time. The last day of school. Percy is at school doing an english essay. But then mrs. O' leary storms in, wanting percy to follow her. When they arrived at the place, Percy sees, Thalia, and Nico. The three suns of the The Big Three. They found out they've been summoned by Persephone, Hades wife. She summoned them because she had a problem. Hades sword was stolen. They wer'e making a new symbol of power, but then it was stolen. Percy, Thalia and Nico have to find it, before it fell into the wrong hands. So they go on an adventure in the underworld. They get a flower of Persephone wich will guide them to the sword. The track leads to Sisyphus, a cheater of death. He tells them that a boy with one eye passed by, and he had the sword. Percy instantly suspects Ethan Nakamura, a server of Kronos. When they move on, they get attacked by Keres, and Percy gets hit, bad. Then they move on, and Nico thinks he knows who helps Ethan escape; Melinoe, the goddess of ghosts. Then they come to a river. The river lethe. If this water touches you, you will forget who you are. Percy uses all his power to come across safely with his friends. Then they see Melinoe, and she tricks Thalia and Nico, but she can't fool Percy, and get's defeated. Then Percy sees Ethan, and .... a titan? It's Iapetus. He holds a big spear, and charges Percy. Percy dodges but falls in the river lethe, with Iapetus. Percy can defend himself against the water, but Iapetus fogets who he is. Thalia and Nico defeated Nico, and regained the sword. Once they brang it back, Bob (Iapetus, but Percy told him he was someone else), healed Percy's wound, and they all had a wonderfull Christmas.