The Traitor (A Percy Jackson and Throne of Glass crossover)
In Camp Half-Blood, a warning is sent. The main seven plus Nico and Thalia, are in grave danger. But what if it's all a trap? What if one of them was a traitor to the other side? And what if the other side isn't their enemy at all? Are they just being led on a wild goose chase? Will Percy be able to save his friends...