Please Note That The Following Individual Books As Per Original ISBN and Cover Image In this Listing shall be Dispatched Heroes of Olympus Series 3 Books Collection Set By Rick The Mark of Athena (Heroes of Olympus, Book 3): In The Son of Neptune, Percy, Hazel, and Frank met in Camp Jupiter, the Roman equivalent of Camp Halfblood, and traveled to the land beyond the gods to complete a dangerous quest. The House of Hades (Heroes of Olympus, Book 4): At the conclusion of The Mark of Athena, Annabeth and Percy tumble into a pit leading straight to the Underworld. The other five demigods have to put aside their grief and follow Percy's instructions to find the mortal side of the Doors of Death. The Blood of Olympus (Heroes of Olympus, Book 5): In the breathtaking fifth and final book in Rick Riordan’s #1 best-selling Heroes of Olympus series, the Greek and Roman demigods must simultaneously prevent Gaea from waking and stop war from breaking out at Camp Half-Blood.