When Carter Kane left on a simple retrieval mission, he didn't expect it to go horribly wrong. Nor did he expect to meet a son of Poseidon and learn about a whole other world of monsters and gods he never knew existed. What he DOES know, is that someone's trying to destroy the world. Again. And it's up to him, Sadie, and his new friends to stop it. Just another day for the Kanes.

Annabeth was slipping and Percy dived to save her; something went wrong. On the surface, Annabeth leads the Seven, desperate to rescue him and unite the camps. Alone in Tartarus, Percy finds himself making harsher choices, discovering darker methods, unlocking deeper powers, tortured and fighting for his life. He swears he's still a good kid. Post MOA