Power of Six (Hardcover, Bound for Schools & Libraries ed.)

John Smith is Number Four, and following a massive battle in Paradise, Ohio, he joined forces with Number Six. Their victory inspired a fellow Lorien named Marina, aka Number Seven, to step forward as well. She's certain it's the sign she's been waiting for. The sign that the time is right for the remaining teens to come together, to fight the Mogadorians--and to win.