The king had just had a nice feast, everyone had gone and he went to lie down. In the quiet of the night, when there was nothing pressing to be handled - he found himself restless and unable to fall asleep.
Don't we do the same in our busy hectic lifestyles? We finally get the opportunity to stop and get some rest and we can't fall asleep. The king, like many of us, decides to read - or course, since he's the king, decides to have someone read to him. He asked for "The Book of the Chronicles" - which is basically his journal of his years of king.
Now here's the thing - he didn't tell his servants what page to turn to or what year of his reign to read, they just happened to pick the page about Mordecai. So then the king asked - "What did we do to reward Mordecai for this?" The answer was nothing - which also goes to Mordecai's character. He had revealed the plot against the king, but had asked for nothing in return - he had simply done it because it was the right thing to do.

So what can we get out of these three verses? In the quiet of night, in the moments where there is nothing pressing and no urgent matters to be taken care of, when you find yourself alone and unable to rest easy - let God grab your attention and listen to the plans He's laying out for you.