When they are cornered by empousai monsters on their way to the Doors of Death, they are rescued by Bob, the former Titan Iapetus whose memory Percy wiped in the River Lethe and left as a janitor to Hades.

Percy and Annabeth land in the River Cocytus in Tartarus and manage to survive the deadly Tartarus by drinking from the River Phlegethon, the River of Pain, which heals mortals. The chapters alternate between the Argo II quest members and Percy and Annabeth and their adventures in Tartarus. Protagonists Hazel, Frank, Jason, Piper, Leo, and Coach Hedge fly the Argo II (a flying Greek ship) across Italy to the Doors of Death in the House of Hades, where they plan to stop the monsters and rescue Percy and Annabeth, who have fallen into Tartarus (the underworld). The House of Hades begins directly after the events of Mark of Athena. This is the only book where all seven protagonists of the Heroes of Olympus series have a featured point of view. The House of Hades is told from an omniscient third-person point of view that switches between the seven members of the quest: Percy Jackson, Annabeth Chase, Hazel Levesque, Frank Zhang, Leo Valdez, Jason Grace, and Piper McLean. This guide is based on the 2019 Disney Hyperion paperback edition. Riordan has a standalone Percy Jackson book forthcoming in 2023: Percy Jackson and the Olympians: Chalice of the Gods. Riordan is the publisher of an imprint with Disney Hyperion that seeks to publish works of fiction that explore world cultures and mythologies.

The House of Hades was written by Rick Riordan, a New York Times bestselling author who explores Roman and Greek Mythology in these two series.

Heroes of olympus the house of hades