It's the February after Gaea's defeat. Camp Jupiter, like everyone else, should be celebrating. But something is causing chaos. Mysterious, sinister incidents are wreaking havoc throughout the camp. Suspicion quickly falls on Claudia, the Fourth Cohort's newest probatio. After all, the mischief started shortly after she stumbled into camp. To find out the truth, delve into the pages of Claudia's personal journal. Through her eyewitness accounts, you'll visit the crime scenes - a row of seats in the coliseum, an underground aqueduct tunnel . . . And you'll be right alongside Claudia when she discovers an ancient secret that may hold the key to Camp Jupiter's safety.