The Stranded, Volume 1 — Mike Carey

In The Stranded, the first Virgin/SciFi book, five ordinary people must face a terrifying question: What if your entire world - your childhood, your family, all your memories - was a lie? For the Stranded, it's true; they're all, secretly, from another world. And now a deadly, otherworldly force has returned to try and kill them, operating through a twisted, altered human called Janus. Their only hope: Tamree, a dark, mysterious woman sent to Earth as their protector. One by one, Tamree must awaken the buried memories of the Stranded - along with their powerful, unique psychic and physical abilities. But even if they can defeat Janus, they must also deal with a deadly threat from one of their own!