Mark of Athena by Rick Riordan

Okay, so I got the book, I read the book, I loved the book.  I really don't want to give to much spoilers, but there isn't much I can do to stop myself.  The Mark of Athena starts with Annabeth and a giant warship.  The Greek and Roman demi-gods meet and manage to avoid killing each other, until Leo goes crazy and fires on Camp Jupiter and that pretty much starts a war.  Percy and Annabeth are re-united briefly before they have to jump aboard the Argo 2, Leo's awesome war ship, to avoid the angry Roman demi-gods.  The nice Roman demi-gods, Jason, Hazel and Frank, jump aboard the Argo 2 as well, and the seven questers get out of there as fast as possible.  After trying, and failing, to figure out why Leo went crazy, they get some supplies to repair the ship, Leo starts a fan club of nymphs before they realize that they don't like Leo, Hazel and Leo meet Nemesis the goddess of revenge, and Echo the girl cursed to always repeat the last thing she hears, all while the others battle some tar monsters.  Then Piper has a dream and they head to Kansas to meet Bacchus/Dionysus/The Wine Dude.  He isn't much help and after he leaves Gaea shows up (not literally but you know, in the earth) and Percy and Jason are possessed by angry spirits and try to kill each other.  Luckily, Piper is able to stop them with her charm speak and a little help from Blackjack, Percy's pegasus.  Once they get back to the ship and revive Percy, they connect the evil possessing spirits to Leo's crazy stunt with the gunpowder.  Finally free of the spirits, the gang follows Bacchus' clues to Atlanta, with Percy and Frank going straight into a trap that, surprisingly enough, Coach Hedge gets them out of.  Meanwhile, the girls spend some freaky quality time with Aphrodite, who is one of the only gods not fighting to remain either Greek or Roman.  Love is always the same, and apparently so are revenge and wine.  Awesome.  So, the seven demi-gods from the prophecy now have like, the three least helpful gods to help them while the others deal with their Greek/Roman sides.  Plus, half of Camp Jupiter is following them on giant war eagles to kill them for wrecking the camp.  Fun.  After a brief battle, they head to the  Mediterranean Sea and towards Rome, completing a quest for Heracles/Hercules on their way.  Once in Rome, the real trouble begins.  Crazy right?  So, Annabeth has this important quest from her mom.  The details are vague, but she basically has to follow the Mark of Athena through Rome and find something important to the Greeks that the Romans stole.  With some help from the god of the Tiber river who looks like Gregory Peck who's friend looks like Meryl Streep, Annabeth starts her quest, going into the underground tunnels of Rome.  Hazel, Frank and Leo are also underground, searching for Nico Di'Angelo, who found the Doors of Death and is trapped by giants.  They follow Hazel towards Nico, or more specifically towards Nico's sword.  Leo is ecstatic when it leads them to Archimedes' workshop and discovers Archimedes' spheres.  And he's not as ecstatic when the evil spirits come back in the form of robots that shouldn't be able to work according to broken wires and such.  It was a trap.  Can they get out?  Across the city, Percy, Jason, and Piper are underground too.  What a coincidence.  Except they have to fight some ancient water nymphs, before they drown in poisoned water.  And Annabeth is battling an ancient enemy of Athena's.  Can her wits get her out of this?  Will the seven be able to save Nico?  And where are the Doors of Death?