Percy abandoned and lost, suffering from amnesia and on the run from the gorgons, finds Camp Jupiter, the Roman camp for demigods. He befriends Frank and Hazel. Together, they win Capture the Flag for the fifth cohort. Mars then claims Frank as his son and launches a mission to save Thanatos, the Greek god of death, from LAceonus, a giant born to oppose Pluto, and assigns Frank as the mission's leader. The trio faces many challenges such as Basaliks, Amazons (a tribe of women), karopis, griffins and very low supplies. They also learn a lot from each other. Percy and Frank discover that Hazel was dead and came back to life, Frank's life depends on a burning stick, and Percy is Greek. Percy regains his memory after drinking gorgon blood to destroy Phineas. They also acquire the world's fastest horse to escape the Amazons, Arion. With Arion's help, they reach Hubbard Glaacier, where they walk into a trap. A hundred shadows of once-living demigods surround them, beyond Thanatos's control. Alceonus appears and taunts them. Thanatos tells them that only the burning stick on which Frank's life depends approx...