The Lost Hero The novel begins by introducing Jason Grace, Piper McLean, and Leo Valdez, three newly discovered demigods who travel to Camp Half-Blood in response to a prophecy. They set off on a quest to prevent the rebirth of the giant king
Porphyrion and rescue Piper's father, who has been kidnapped by another giant,
Enceladus. Jason, who has
amnesia, also begins to remember pieces of his past throughout the book most importantly, he comes from a Roman camp for demigods. Camp Half-Blood resolves to seek out this other camp both to gain allies in the fight against Gaea, the giants' mother and commander, and to locate the missing demigod, Percy Jackson.
The Son of Neptune The novel opens with Percy Jackson, struck with amnesia, discovering Camp Jupiter and meeting several Roman demigods. After receiving a prophecy from
Mars, Percy, Frank Zhang, and Hazel Levesque travel to Alaska to stop the rise of the giant
Alcyoneus and free the god
Thanatos, whom the giant has captured. After successfully completing their mission, the group returns to Camp Jupiter to defend it from yet another giant,
Polybotes, and his army. After repelling this invasion, the demigods from Camp Jupiter go to meet the delegation from Camp Half-Blood, who arrive in the flying ship known as the
Argo II. This book is set in June.
The Mark of Athena After the
Argo II unintentionally fires on Camp Jupiter after Leo Valdez is possessed to attack it, the seven demigods of the "Prophecy of Seven" Percy Jackson, Annabeth Chase, Leo Valdez, Piper McLean, Jason Grace, Frank Zhang, and Hazel Levesque rush to escape the angered Roman campers. The
Argo II is damaged, and the group splits up to find supplies to help Leo fix it. Hazel and Leo go out to try to find
Celestial bronze and lime for
calcium carbonate when they encounter
Nemesis, the universal (meaning Roman and Greek) goddess of revenge. Nemesis's form is different for both Leo and Hazel, Leo seeing his Aunt Rosa and Hazel seeing one of her old teachers. Nemesis tells Leo that the gods are split between their Greek and Roman forms, making them disoriented and confused. This means a civil war is on the rise between the Romans and the Greeks. Nemesis tells Leo that he will be the "seventh wheel", and not fit in with the Seven. She also tells Leo that he will stumble upon a problem that he cannot solve. Nemesis offers Leo help for a price. She leaves Leo and Hazel frazzled, confused, and angry. The Seven travel to Rome, guided by the "Mark of Athena", a magical talisman designed to lead children of Athena to the missing
Athena Parthenos. During their journey, they hear that Nico di Angelo has been captured by the
Aloadae, and go to rescue him. Although they successfully free him and locate the statue, Annabeth and Percy are pulled into
Tartarus by Gaea, and Nico promises Percy to get the other demigods to the "Doors of Death". This book is set between June and July.A graphic novel adaptation "The Mark of Athena Graphic Novel" was released September 26 2023.
The House of Hades In Tartarus, Percy and Annabeth travel towards the "Doors of Death", the only pathway back to the mortal world, with help from
Bob the Titan, hoping to escape and simultaneously stop more monsters from getting through. In the mortal world, the remaining demigods search for the mortal side of the Doors to help open them. They also meet with Reyna Avila Ramírez-Arellano, a Roman demigod; she, Nico, and Coach Hedge leave with the Athena Parthenos from Epirus, Greece, and Shadow Travel to Camp Half-Blood. Once reunited, the original seven sail for Greece, where they expect Gaea's main force will gather. This book is set in the first half of July. The Graphic novel adaptation "The House of Hades Graphic Novel" was released 24 September 2024.
The Blood of Olympus While Reyna, Nico, and Coach Hedge travel towards Camp Half-Blood (where the Romans are preparing to attack the Greeks), the seven of the quest travel to Athens. With help from the gods, the demigods defeat the giants in Athens, where Leo sacrifices himself to defeat Gaea. He is later resurrected by his bronze dragon
Festus and goes to find his crush
Calypso. Unaware that he is alive, Camp Half-Blood and Camp Jupiter mourn his loss, determining to become allies and prevent such a deadly war from happening again. This book is set in the second half of July. ==Supplementary works==