CAMP HALF-BLOOD is the only place for children of the Olympian gods to live. Where else can they fight monsters and practise archery with flaming arrows and explosives? But Camp Half-Blood's latest recruits - Jason, Piper and Leo - haven't been brought here for fun. A major problem has arisen. Hera, Queen of the Gods, has been imprisoned. They are the chosen ones to save her from great evil - with only four days to complete their quest. And that's not all. Percy Jackson, hero of the half-bloods, is missing. The second great prophecy has begun. But the half-bloods have no idea how many enemies they've awakened. This is a war they cannot win . . . Can they?