Books in the Shadows of the Immortals series

Lexi is back from the underworld, heartsore but determined to exact some sweet vengeance on the shadow shapers. To do that, she'll need Zeus's help, but Zeus is trapped in the wires, slowly disintegrating into nothingness. Without his lightning bolt, he's toast. So all she has to do is find the missing pieces of the lightning bolt and her troubles should be over, right? Wrong. She may have found out who she is, but her memory is still full of holes-which will make tracking down the lightning bolt kind of tricky. And when the shadow shapers strike again, threatening the people she loves, it's clear that Zeus isn't the only one running out of time. Lexi's had tough gigs before, but unless she frees Zeus and defeats the shadow shapers, Olympus will fall. And that kind of pressure can really ruin a girl's day.