Percy Jackson is back for a followup adventure, and while most of the cast (Percy, Annabeth, and Grover) is back, plus a few new characters (Clarisse, offspring of Mars, and a half-brother for Percy, Tyson, who's also a cyclops), it feels like an inert progression of the story for the Half-bloods (or demigods, the offspring of gods and mortals). As their Camp Half-Blood's magical barrier has been shattered, bits of clues lead to a quest for something that will restore the barrier and keep the camp safe. The story structure is pretty much paint-by-numbers for this genre, but it does allow Percy to shine when needed, and also do some political maneuvering to keep from raising Clarisse's ire and competitive nature, while keeping the focus on their main objective. The antagonists for the story is the weak point, but for fans of the book series, it's a decent installment to the Percy Jackson film franchise. I give it 2.5 stars, or a grade of C+.