Empowered book 1: "Run"

Charlie Martin was the perfect guy. All the girls wanted him. He had flawless grades. He was the embodiment of school spirit. He had it all. After he graduated high school he'd get a degree in engineering, get married, and make his family proud. At least, that's what everybody thought. A few days after her brother leaves for college, Cara Martin picks up the phone only to discover that Charlie never showed up. There's a search, and it comes up empty. Charlie is presumed dead. Case closed.

A year later, Cara's senior year of high school is coming to a close, and she can't wait to go to college and achieve her dream of becoming a nurse for Charlie's sake, if not her own. Only, it's not that simple. Cara is walking past the English wing at school, and out of nowhere she finds herself in her brother's arms. Charlie is perfectly fine, but if that's the case, where has he been all this time? How did he get into the school without anyone seeing him? Why does he keep saying "Thank God you're still ok?" And why does he have a gun?