Summary from Amazon:
In The Son of Neptune, Percy, Hazel, and Frank met in Camp Jupiter, the Roman equivalent of Camp Halfblood, and traveled to the land beyond the gods to complete a dangerous quest. The third book in the Heroes of Olympus series will unite them with Jason, Piper, and Leo. But they number only six–who will complete the Prophecy of Seven?The Greek and Roman demigods will have to cooperate in order to defeat the giants released by the Earth Mother, Gaea. Then they will have to sail together to the ancient land to find the Doors of Death. What exactly are the Doors of Death? Much of the prophecy remains a mystery. . . .With old friends and new friends joining forces, a marvelous ship, fearsome foes, and an exotic setting, The Mark of Athena promises to be another unforgettable adventure by master storyteller Rick Riordan.
Give me more Leo and Annabeth. We’ve never heard much from Annabeth before now and Leo is entertaining. I really missed Frank and Hazel, who both have interesting storylines and problems still not revolved. Otherwise, all the characters are as fun as ever, old friends I enjoyed hanging out with again. No one solves their problems with muscles or swords, which is a hallmark Riordan continues to put in his stories. The author is good at finding inventive ways for his heroes to untangle themselves from trouble.
Where I think the book suffers most is from middle-book syndrome. Here Percy and the gang are attempting to head to Rome to face off with Gaea. While the previous books had a ton of mystery behind various aspects of the plot and the coming threats, the reader is told up front what the teens will face and who and why. The heroes are led by their noses and the reader is too. That does not diminish the fun of the story. The adventure is there, but there are less moments where you’re gasping at an unexpected reveal. Not that the gut wrenching finale is not good. It is! That’s what saves the story and pushes through. I have to say this: Riordan had courage when writing the end of “Mark of Athena”, an ending that is difficult to speak of without ruining. So you get spoiler warning… To read click show
As the story moves to the Mediterranean, the adventure picks up and novel kicks into high gear, running to the finale mentioned in the spoilers. By the ending there is so much momentum leading into the next book that I cannot help but be excited.