. "To retrieve the Sword of Hades which Persephone had illegally forged and then lost."@en . . "Nico di Angelo"@en . . "The Demigod Files"@en . "The Quest for the Sword of Hades was undertaken by Percy Jackson, Thalia Grace, and Nico di Angelo to retrieve Hades' Sword before its thief escaped the Underworld."@en . "Thalia Grace"@en . . . . . . "The Quest for the Sword of Hades was undertaken by Percy Jackson, Thalia Grace, and Nico di Angelo to retrieve Hades' Sword before its thief escaped the Underworld."@en . . "3"^^ . "Quest for the Sword of Hades"@en . "None"@en . "The sword is retrieved and Iapetus loses his memory"@en . "None"@en . .