I

Ruin is coming. Gaea is dead, Kronos is gone, and Camp Half Blood is finally peaceful. Too peaceful for anyone who's smart. Secrets are revealed, boundaries are tested, and lives are sacrificed. The line between right and wrong is crossed and must be shattered for survival. Creatures concealed in crystal hoods fight the war that took their Hero from them without a trace.

The demigods of Camp Half Blood believe the only way to find their missing camper-Percy Jackson-is to investigate the supposed death of Leo Valdez further. Instead they learn a lot about a group known as the Dark Elites, who have followed the same pattern their whole lives.

Run-Hide-Fight-Die.

To save the world from Chaos, they let it fall to Ruin.