Not yet halfway through this 5-book-series, I'm growing more and more certain that it would've been better as a trilogy. While the plot moved faster than the previous book, a good chunk of it is spent in characters we already met.
Sure it's cool to see how these beloved characters are doing, in fact, it's what makes the world feel so alive: it really seems like people are living their lives outside the main plot. But differently from The Hidden Oracle, where these characters appeared here and there to chime in, in The Dark Prophecy they take a protagonism that should be the new cast's.
The best scenes in the book are the dinamics between Apollo (who's charisma rivals Percy for my favoritism) and Meg or Emmie, and the ingenious decision to bring the villain as one of his former lovers. When the narrative actually focuses on it's own set of characters, I enjoyed it immensely. They are interesting and funny and I wanted to know more. I did not need to read about Calypso and Leo bickering for pages and pages when this story is not about them. Take them out and it doesn't change much.
This is clearly a direction the series unfortunately is taking and, because I really enjoy the actual story being told, I wish Rick Riordan trusted it to stand on it's on instead of relying on nostalgia, because it is strong enough to do it.