Here is my teaser from Tomorrow's Guardian by Richard Denning (Page 3):
Fifty enemy warriors closed in on him from all around. His mouth felt dry. Shaking with fear he fired his revolver, heard the hammer click on an empty chamber. He fumbled for his sword, knowing he had only moments to live...
"Tom, wake up lad; wake up now! Your friends will be here soon."
Tom Oakley opened his eyes, sat up in bed and stared wildly around his room, taking in the PC in the corner, a heap of abandoned clothes and trainers on the floor and the Nintendo DS on the bedside cabinet. Finally, he turned to where his father stood at the open door and gave him a bewildered stare.
His father's eyes narrowed and he came and sat on his son's bed. Reaching over, he swept Tom's hair to one side and touched his forehead to see if it felt hot.
"What is it lad? Did you have another of those nightmares?"
"One of those dreams where you think you're someone else?"
"They seem so...real, Dad," Tom answered.