The House of Hades

After Percy Jackson and Annabeth Chase fall into Tartarus, the Argo II struggles toward Epirus and the House of Hades. The ship is repeatedly driven back by mountain gods, and Hazel Levesque takes a decisive step when Arion leads her to Hecate. At a magical crossroads, Hecate shows Hazel disastrous possible futures and sends the crew on a northern route through Bologna and Venice. She also warns that Hazel must learn to control the Mist and defeat a sorceress before the quest can reach the Doors of Death.

In Tartarus, Percy and Annabeth survive their fall only through desperate improvisation: Percy summons water to cushion them, and Annabeth forces them onward despite injury, hunger, and despair. They drink from the fiery Phlegethon to heal and follow enemies toward the Doors of Death. When empousai trap them, Bob the Titan—formerly Iapetus, now an amnesiac ally because of Percy and Nico’s past actions—rescues them. Bob guides them through Tartarus, though Annabeth fears his old identity may return.

Above, the Argo II follows Hecate’s route and is delayed by the Kerkopes Akmon and Passalos, who steal important equipment. Leo Valdez captures them in Bologna, recovers a damaged astrolabe and a book connected to Venice, and sends the thieves to New York to harass the Roman forces. In Venice, Frank Zhang, Hazel, and Nico seek the book’s owner and encounter katobleps whose poison nearly kills Hazel. The farming god Triptolemus refuses help because of his hatred for children of Hades, but Frank bargains, then annihilates the katobleps and earns Mars’s favor. Triptolemus cures Hazel and Nico and reveals that the heroes must eat special barley before drinking a poison chalice at the House of Hades.

Percy and Annabeth’s path grows darker. The arai, spirits of curses, blind Annabeth and afflict Percy with the pain of old enemies’ dying curses. The arai also shake Bob’s trust by revealing Percy erased his memories and never visited him afterward. Percy apologizes, and Bob chooses friendship, destroying the arai and leading them to Damasen, a peaceful giant cursed to fight the Maeonian drakon forever. Damasen cures Percy’s poison but initially refuses to leave his swamp, explaining that the Doors of Death lie at Tartarus’s heart and that Death Mist from Akhlys may be their only disguise.

Meanwhile, Jason Grace and Nico seek Diocletian’s scepter in Split. Favonius reveals that Cupid holds it, and Cupid forces Nico to admit the secret shame that has isolated him: he once had a crush on Percy. Jason supports Nico after the confession, and Nico claims the scepter, which can command Roman ghost legions. Soon afterward, Khione attacks the Argo II, freezing Jason and hurling Leo into the sky. Piper McLean defeats Khione and the Boreads by using charmspeak more subtly, awakening Festus through emotional appeal and saving the ship from a wind bomb.

Leo survives by crash-landing on Ogygia, where he meets Calypso. She reveals that the gods never freed her and that Ogygia’s raft has failed to appear, trapping them both. Their hostility softens into partnership as Leo builds tools and a guidance console. Gaea tempts Calypso to kill him in exchange for freedom, but Calypso rejects the bargain. When the raft finally appears, Leo leaves after a kiss and swears on the Styx that he will return for her.

In Tartarus, Percy and Annabeth obtain the Death Mist from Akhlys, but she betrays them. Percy discovers he can control poison as if it were water and nearly kills Akhlys with her own venom until Annabeth stops him, frightened by the power. Nyx then confronts them, but Annabeth stalls her with sarcasm and manipulates Nyx’s children into chaos, allowing the pair to flee through the Mansion of Night. They cross the River Acheron and reunite with Bob near Tartarus’s heart, where a vast monster army surrounds the Doors of Death.

The Argo II, damaged and missing Leo, reaches the palace of the South Wind. Jason chooses his Greek path, transforming Auster into Notus and securing wind horses to tow the ship to Malta, where the crew reunites with Leo. Black lightning signals that the Doors of Death are opening, so they rush to Greece and descend into the Necromanteion. After drinking the ritual poison, the group is ambushed. Hazel and Leo are separated toward the Doors, while Frank, Jason, Piper, and Nico face an army. Jason resigns his praetorship and names Frank praetor, allowing Frank to command the Roman dead with Diocletian’s scepter and win the battle.

At the Doors in Tartarus, Koios tempts Bob with his old Titan identity, but Bob chooses Percy and Annabeth. Hyperion and Krios guard the chained Doors, but Tartarus himself manifests and destroys them, taking a physical form to kill the demigods. Bob and Small Bob fight him, and Damasen arrives on the Maeonian drakon, choosing a new fate. Percy and Annabeth cut the chains and enter the elevator, while Bob holds the button for twelve minutes and Damasen battles Tartarus, allowing them to rise toward the mortal side.

Hazel and Leo reach the upper Doors, where Pasiphaë traps them in a recreated Labyrinth and Clytius waits as Gaea’s giant of darkness. Hazel masters the Mist by turning Pasiphaë’s illusions against her, banishing the sorceress, and Leo hits the button to open the Doors. Percy and Annabeth collapse out of the elevator. Hazel breaks the Doors’ chains, removing them from Gaea’s control, and Hecate arrives. Frank, Jason, Piper, and Nico join the fight, and together with Hecate’s fire they destroy Clytius. Hazel and Nico then shadow-travel everyone out as the House of Hades collapses.

On the surface, the reunited heroes learn that Reyna has reached them. They decide the Athena Parthenos must be returned to Camp Half-Blood by a Roman to prevent war between the camps, while the Argo II sails for Athens to confront the giants and Gaea. Nico volunteers to shadow-travel the statue with Reyna, and Coach Hedge joins them. Percy and Annabeth, grieving Bob and Damasen, rejoin the crew as the missions divide: one group carries hope west to heal the Greek-Roman rift, while the Argo II heads east toward the final confrontation.