Now it's up to Percy and his friends: Their arch-enemy Kronos is making his final move and marching towards Olympus, right into the heart of New York - while the Olympian gods have all left to fight the resurrected monster Typhon! Together with Artemis' hunters and the city's resurrected monuments, the young demigods try to defend the seat of the gods, but to make matters worse, they also have a spy in their own ranks. Good thing at least one goddess has stayed behind in Olympus ...