Kronos has finally risen and is attacking Olympus with Luke as his vessel. Percy, Annabeth, Grover, and Thalia race against time to save their home. Meanwhile, somewhere on Earth forces previously believed to be faded are stirring, and a dark plan that will tip the scales of sanity will rise. Will Percy and his friends be able to fight against these forces? And what does our ever mischievous Mephisto Pheles have to do with this? Why does everyone suddenly start pointing crude fingers at Poseidon? And what does Kronos know that others don't? More importantly, why does Percy have a tail?