This review contains *SPOILERS* for the first half of the book.
I went into this book very cautiously. I liked the Percy Jackson series, but by the end of the series I was a little weary of all the characters and plotlines that settled out exactly as I expected them to. I wasn't sure if this would just be more of the same, or have even less interesting characters.
But, lucky, I was pleasantly surprised. I loved all three main characters, which rarely happens in any book, and I was definitely not expecting it from Riordan (I like Percy, but am pretty meh on the other leads). I found Jason, Leo, and Piper to all be lovely and interesting in different ways. Jason is a natural leader but he's also really sweet, and doesn't remember anything, which is his issue. Leo is an inventor-genius with a snappy wit, but is haunted by guilt (DUN DUN DUN). Piper is fierce and smart but has her weak spots. Did I mention I liked the darker backstories? Like Leo's mom's death and Piper's insecure movie star dad? Yeah, I did, quite a bit.
All of those things are well and good, but these characters were just extremely likeable for me, and since I read primarily for characters, I would have enjoyed this book even if the rest of it was meh.
But it wasn't! Riordan didn't just do the same old plots. I mean, it's a similar formula, with the three heroes on a quest, but the way he incorporated the Roman pantheon (and everything that that implies), the darker backstories to the three main characters, and villains that we weren't able to see before, because they're DEAD...all that was lovely. Plus, we're getting Hera/Juno in a big way, and Romanies like Khione and Aeoleus. Lots of possibilities here. I also liked that the Hephaestus/Vulcan cabin is more important, because of Leo and also because of all their cool inventions! Festus, too, was a great addition to the story and especially Leo's journey.
The overall plot with the sleeping soil-covered lady/the giants/the living dead is really cool, too. In some ways I think it's cooler than the whole Kronos thing. Most of the major Kronos plot points, especially the ones involving Luke, I spotted from book one (I'm not bragging, really! It was transparent!). In this book, I was never sure what was going to happen. Plus, Riordan has now enabled himself to bring characters like Minas and Medea in, which is ALWAYS a great idea. :D So many villain opportunities now!
The main things I didn't like were a couple of characters, specifically Coach Hedge and Chiron. Coach Hedge had all of the things I disliked about Grover and NONE of the things I liked about him. Pretty much any moment where Hedge was unconscious/frozen/gold were good times for me. And Chiron....don't get me started on Chiron. Gandalf or Dumbledore or Oreius, thou art NOT. I'm never sure if Riordan means for him to be a strong, wise, mentor type or not. Certainly the MCs in Percy Jackson and this book view him that way. But when has Chiron ever been helpful? He's always really depressing and just discourages and emotionally abuses the MCs, and then let's them go to fight and die. /rant
4/5 stars from me. I'm excited for the next book and am actually considering picking up The Red Pyramid now, which I was definitely on the fence about before.
PS-Reading this book while also reading The Aeneid is a bit of a mind trip.