Elemental Overdrive (Rewrite)

An author and his two friends are called into a world similar to their own. A stark difference being the zombie-like infected, high tech weaponry, and supernatural energy. How long before the three regular high school freshman get to go back home? What happened to this world? For what purpose do they serve in this strange world? These are the questions that go on in their head as they proceed to aid this similar yet foreign place.