After the final battle, things have calmed down and Percy has finally gotten to live a normal life with his girlfriend Annabeth - or, as normal as a half-blood's life can be. The story now passes on to Caleb Harrison - the son of Hades and half-brother to Nico Di Angelo. Life seems peaceful, until Caleb needs a favour from his deadly father, for a mission he's hoping to go on soon. But Hades doesn't just help for free, even for his son. So Caleb, and his group of wacko friends, complete a small task for Hades - retrieveing a small object that they don't know may release the greatest trouble the Gods have ever seen. Kira O'Malley, daughter of an enemy the Gods didn't want to face again, was imprisoned in the earth by the Gods over a year ago. With the mysterious object that Cale got for his father, she is freed to be bound to Hades and fulfill his every request. When the bloodthirsy fifteen year old is sentenced to help Cale with his quest from the Gods, can they figure out how to get along despite their differences?