In this final installment of the Percy Jackson and the Olympians series, the battle truly rages for New York, for Mount Olympus, and for the world. Titans are now fully reforming and the demigods/Heroes/half-bloods must fight to save everything. It is incredibly difficult as the gods of Olympus are facing attacks on multiple fronts from the Titans Oceanus and Typhon.
The book starts out with a covert attack on Luke and Kronos’ supposed command ship Princess Andromeda. This ends with Percy marooned on Calypso’s magical island Ogygia in order to recuperate. When he returns to camp, all hell breaks loose as they are facing a spy, an increasing number of opponents, and greater losses of life. Nico, son of Hades, made a suggestion to Percy of taking on Achilles curse, dipped in the River Styx and becoming invincible, to which Percy finally agrees.