Annabeth, Leo, and Jason are searching for Piper, who is missing. Atalanta, a mortal, may just be the key to finding Piper, but why is Piper gone? Gaea is rising and the gods don't even know a war is going on. Everyone needs a hero, but can Atalanta be that hero? This is set in between The Lost Hero and Son of Neptune.

Set three years after the end of The Crimson Crown, this is the story of Aarin, a Demonai clan member trying to find his way in court and bring peace between the wizards and clans, and Princess Mellony, 16 years old and trying to figure out how she fits into the Queendom. But Aarin soon discovers a dangerous plot against Mellony, and they might be the only ones who can stop it!