Hera [ said like she's cursing, because she...basically is... ] decided the only way we'd defeat the giants and Gaea - spoiler alert, those were a thing - was if the camps combined forces and decided the best way to do that would be to kidnap and mindwipe someone from our camp and switch them out with a kidnapped mindwiped member of their camp.

[ she's still salty. ]

She took Percy. We got Jason Grace.

[ ...and she'd taken ages to warm up to the guy. but jason had started off on the wrong foot by not being percy jackson. ]

Eventually we tracked Percy down at New Rome - their camp - and then a bunch of stuff happened and we had to quest to actual legitimate Greece. And I had to find the Parthenos on the way. Again: a lot happened.