After two hours

The two hours quickly flew by for Karyn and she had just managed to get finished before Jon started to change back.
"That hurts," Jon said as he regained his normal form. "You just don't realize how stiff you feel when you suddenly change back after being forced to stand still like that for all that time."
He started to walk round the room to get rid of the stiffness but all the while he kept his eye on the stone which Karyn had carelessly thrown onto his bed. Since Karyn was watching him exercise he knew that for the moment she had forgotten the stone. As he got nearer to the bed he made a sudden lunge and grabbed the stone.
"Right you've had your fun," said Jon as he took hold of the stone. "Now it is my turn. I wish that you were a...