"The Sea of Monsters" by Rick Riordan
Change is always difficult when reading a series. You're like, "OMG, I enjoyed that first book, I hope the second one kind of does the same thing." Then, you realize, Rick Riordan would be doing himself and his readers a giant disservice if he did that, so then, you realize, "Please do something different."
I think I enjoyed the second installment more than the first. I enjoyed the reading-aloud that I got to enjoy through the audio addition, I enjoyed the "frenemy" relationship that begins to bud between Annabeth and Percy (although, you realize it's really just tween "looourve" and so they don't know how to work with the infatuation, so they just annoy/enjoy each other).
We find the heroes on another quest, this time they need to save Grover, who thinks he found his bestie Pan, but they realize that they found the ever-famous Cyclops (ursa major). There's the golden fleece, there's trouble at Camp Half-Blood, they're on the water most of the journey...and the way they incorporate the "sea of monsters" and where it is in Western Civilization is perfectly brilliant.
Hurray for Tyson! Riordan incorporates a cyclopean character that is the equivalent to a sweet puppy-dog, and he just does everything right, especially when he loves "ponies!" He embarrasses Percy and then Percy realizes that even though you can't choose family (half-brothers), you can still love them, and also learn from them.
I think one of my favorite bits was about donut shops popping up, and whenever there's a donut shop, there's monsters...
It continues to enchant, and although the language isn't the most striking, Riordan captures the voice of Percy, and that alone catapults the series forward as they get closer to the showdown against Kronos and his minions.