Thalia Grace, Percy Jackson, and Annabeth Chase go there as Pseudo Students (due to mist) to help Grover Underwood recruit new demigods, Nico di Angelo and Bianca di Angelo, who are unknowingly children of Hades. They fight Dr. Thorn there, the assistant principal of Westover Hall; Annabeth gets kidnapped by Thorn; and the rest of the demigods were saved by and introduced to Artemis, the goddess of the Hunt and the Moon, and her Huntresses. Also, it is where they are first introduced to Apollo, Artemis' twin brother and the god of the sun, who takes all of them and the Huntresses to Camp Half-Blood in his sun-mobile, which is a Maserati.
|Magical Locations:||Aeolia | Camp Half-Blood (Grove of Dodona) | Camp Jupiter | Cave of Trophonius | C.C.'s Spa and Resort | Daedalus' Workshop | Lotus Hotel and Casino | Mount Othrys | Ogygia | Olympus | Pan's Cave | Sea of Monsters | The Labyrinth | Tartarus | Underworld | Waystation|
|Cities, States, and Towns:||Alaska | Bar Harbor | Bologna | Chicago | Detroit | Gila Claw | Indianapolis | Jamestown | Long Island | New Mexico | New York City (Manhattan) | Quebec | San Francisco | Dalmatia (Split) | Vancouver | Venice | Westport|
|Other Locations:||Apennine Mountains | Aunty Em's Gnome Emporium | Carlsbad Caverns | Crusty's Water Bed Palace | Empire State Building | Gateway Arch | Grand Canyon | Greece | Hoover Dam | Italy | Junkyard of the Gods | Mount Diablo | Mount Etna | Mount Saint Helens | Mount Tamalpais | Pikes Peak | Polyphemus' Island | ROFL | Rome | Triple G Ranch | U.S.A. | Waterland|