The House of Hades

Necromanteion of Acheron

The House of Hades (Doors of Death)

The remaining demigods on the Argo II fight their way to the Necromanteion to close the Doors of Death from the mortal side while Percy and Annabeth close them from Tartarus.

Bologna

The demigods encounter the thieving Kerkopes near Bologna and must outsmart them to recover stolen items.

Venice

Hazel and Frank battle Katobleps in Venice. They also meet Triptolemus, who demands a favor before helping them.

Diocletian's Palace

Palace of Diocletian

Jason, Nico, and Piper journey to Diocletian's Palace in Split to retrieve the Scepter of Diocletian, which can summon the ghosts of Roman legions.