The Blood of Olympus by Rick Riordan and Nick Chamian

Though the Greek and Roman crewmembers of the Argo II have made progress in their many quests, they still seem no closer to defeating the earth mother, Gaea. Her giants have risen—all of them, and they’re stronger than ever. They must be stopped before the Feast of Spes, when Gaea plans to have two demigods sacrificed in Athens. She needs their blood—the blood of Olympus—in order to wake. The demigods are having more frequent visions of a terrible battle at Camp Half-Blood. The Roman legion from Camp Jupiter, led by Octavian, is almost within striking distance.

Though it is tempting to take the Athena Parthenos to Athens to use as a secret weapon, the friends know that the huge statue belongs back on Long Island, where it might be able to stop a war between the two camps. The Athena Parthenos will go west; the Argo II will go east. The gods, still suffering from multiple personality disorder, are useless. How can a handful of young demigods hope to persevere against Gaea’s army of powerful giants? As dangerous as it is to head to Athens, they have no other option. They have sacrificed too much already. And if Gaea wakes, it is game over.

This has been my cause of death twice now,😪

I have that feeling you get at the end of a long series. It's strange that it's over!

I made a point to reread the whole Heroes of Olympus series before this book. I was trying to do it before the final book came out, but I was still 1.5 books behind when release day came. I managed to keep myself rereading before diving into the new book, and I'm glad I did. I didn't remember the first couple of books very well and I felt like I really knew the characters much better.

SpoilerI think it's interesting that there were no chapters from Percy or Annabeth's POVs, but the first book in this series didn't have Percy in it at all, so maybe it was a bookending thing. I did feel like, after a book full of scenes with Percy/Annabeth alone together in House of Hades, there wasn't enough resolution for them without any of their POVs.

I'm really glad that Leo ended up with Calypso after he “died”

Rick Riordan announced a series called “Magnus Chase and the gods of Asgard” which is obviously Norse mythology, but people also wondered if he's related to Annabeth Chase. There was a throwaway comment made by Annabeth about an uncle and cousin in Boston that she hasn't seen in a long time. I'm guessing that's the tie-in.