Robb Stark goes to treat with Renly Baratheon at Bitterbridge and the outcome of the War of the Five Kings is different. In typical Westerosi fashion, characters are brought together and torn apart just like that. Follows the idea that one different action affects the entire world.

After defeating Gaea, Greeks and Romans are looking forward to settling down. However, they live in a mythological world, so now the eight demigods- Jason Grace, Piper McLean, Percy Jackson, Annabeth Chase, Frank Zhang, Leo Valdez, Hazel Levesque, and Reyna Ramírez-Arellano set sail again aboard the rebuilt Argo II, journeying to stop their most formidable foe yet.

Percy, Jason, Piper, Annabeth, Hazel, Leo, Frank, and Reyna must confess the secrets they've been hiding from the others to get Eurus, the god of the East Wind, to let them free from Mimas, the bane of Hephaestus, and Khione.