Overall, I enjoyed the plot of this book and I enjoyed how it was written. However, I found most of the perspectives (apart from Percy and Annabeth's) to be weaker and suffered from quite a lot of telling and not showing. Many plot points and character developments felt very forced and only shoved into the book because Riordan decided he wanted character's storylines to end a certain way and he hadn't used the earlier books to properly lay the groundwork.
 
I loved certain parts of this book so much I wish the overall rating could be higher, but when viewed as a whole, and when I factor in the much weaker elements of the story, I don't think I can confidently give this book a 3.5, so I have to leave it lower at a 3.25