The Triple G Ranch is located somewhere in Texas and is the home of the monster Geryon and Eurytion, the immortal son of Ares. The two raise an assortment of mythological animals on the ranch, or sell out space on the ranch for profit.Percy, Grover, Annabeth, and Tyson encounter Geryon, Eurytion and Nico at the Triple G Ranch. The group learns that Geryon is selling some of Apollo's Cattle and other creatures as meat for the Titan Army. Percy makes a deal with Geryon, on the assumption that he and his friends (including Nico) will be set free if he cleans the stables of Geryon's carnivorous horses. He tries to clean the stable the same way it was done thousands of years ago, but a river naiad won't let him. She gives him a seashell and Percy finds a way to use that to clean the stables. He returns to the house but Geryon points out that, since Percy never made him swear on the River Styx, he does not have to honor the agreement.
Percy fights Geryon, but as Geryon has three chests, he is very hard to kill. Getting an idea, Percy runs into the house, grabs a bow and prays to Apollo and Artemis to help him make this one shot, and shoots it sideways through all three of Geryon's chests and killed him. Percy later finds out that Hera was the one who allows Percy to make the shot successfully. Later, Percy insists that Nico try to summon his dead sister, Bianca, but at first he doubts it will work. When Bianca does appear, she tells Nico to forgive Percy, as it was not his fault she died. Afterward Percy gives Eurytion ideas on how to switch the rule of command, he lets them continue on safely, with Nico staying at the Ranch. It is now run by Eurytion.