This was a really good book. It may even be my favorite of the series. It gets right down to business from the beginning. The fight is in full force. Poseidon is battling to protect his kingdom under the water, the half-bloods must defend Camp Half-Blood and the city of Manhattan, and the gods take their own stand leaving Olympus defenseless. 
 Percy has to face some serious obstacles in this book and he becomes the true leader I've been wanting to see in the series. He leads his army against Kronos even when the odds are stacked up against him. Annabeth is always at his side and always makes a great companion with Percy. I loved that in this book you find out about Anabeth and Lukes past together and what led him to do what he did. This book was all-around very good.