In a kingdom, far away there was a prince and princess.  They loved playing with each other.  Both of them loved playing tag as well as hide and seek.  In tag, the Prince always lost because his sister was very fast.  Also the prince could never sneak up on his sister because he was way too noisy. 

They were not very good at hide and seek either.  The prince could easily find the sister because he could easily see her since she glows in the dark.   Though they were both bad at the games they loved each other and played often.  The parents were not so happy though because of the ruckus they made while playing.  The king and queen tolerated the noise because they loved their children very much.

One day, their uncle and aunt decided that they wanted to take over the kingdom and managed to get rid of the king and queen.  The prince and princess managed to escape in time because of some loyal servants.  Their uncle and aunt knew that their place in the kingdom would never be secure as long as the children lived.  They sent out an army after the children.  The chase continue to this very day. 

That is the reason you sometimes see lightning and hear a thunder not far behind.  The prince and princess are running from their pursuers.