In Search of David

Something strange has happened in the small city of Seabrook, Texas. After what seems to be a disastrous earthquake, a girl finds her best friend missing, and a strange soldier dying on her apartment floor. The soldier gives her a weapon and a warning before dying, and soon it becomes apparent that something much, much bigger than an earthquake has happened.
With the help of a kind teenager named Leroy, she sets out, determined to find her best friend at all costs. Soon they realize they are way in over their heads, with nothing but quick-thinking and a vague plan on their side.