Up on the surface, there’s been a major earthquake so the kids get mostly ignored even though they popped up out of the water in giant bubbles.  Percy puts together that the whole ‘blame Hades’ thing was a ruse to get them on the wrong side of the country and unable to deliver the bolt.  And the mastermind behind all this?  Ares!

Well, sorta.

Ares shows up to gloat about how he’s set all of the Big Three against each other, by stealing the bolt, helm, and then killing Percy, ensuring everyone has something to get pissed about.  But when they ask why he bothered to send the bolt into the Underworld with Percy, he gets confused, and it’s clear that part was someone else’s idea.

Ares tries to kill Percy with a boar he summoned, but Percy gets rid of it because, duh, they’re still on the beach and he can just call up water to do his bidding.  Then he challenges Ares to fight him personally.  After much bantering and getting tokens from his two friends, the fight between godling and god is on!

Somehow, despite the fact that Ares is a god and Percy has had exactly one swordfighting lesson, he doesn’t immediately die.  He does get kicked around, but apparently that one lesson was enough to learn him how to defend against the GOD OF WAR.

Cops show up, but I don’t know why.  Ares just explodes their cars to get rid of them, and then it’s right back to the swordfighting.  Percy backs into the water little by little, getting Ares to follow him, and…only once in the water realizes that he can use it to his advantage?  Huh, and here I thought he was heading that direction on purpose, but nope.  He just stumbles into doing the right thing.

Was he planning to win using his “learned it in one lesson” sword skills?

He ends up smashing Ares with water and then stabbing him in the foot.  Ares gets set to keep fighting, because come on, it’s just a flesh wound.  Then the…sky goes dark?  Sorta?  And Ares concedes the fight and curses Percy.

For winning the fight, Percy also gets the helm.  The Furies show up after Ares is gone and they saw the whole thing, so Percy gives them the helm to return to Hades.  Percy apparently has figured out what caused the darkness and made Ares stop fighting, which was the same thing from the Tartarus pit, but he declines to tell the audience.  I guess this book has moved on from not telling Percy things to not telling us things, because there must always be someone kept pointlessly in the dark.

They decide that they’re going to have to fly back to New York on a plane, in spite of all the reasons they couldn’t do it at the start of the book.