Help Me Finish Little Miss Litty

Help I'm stuck!

Throughout the story, I have a demon insisting that people play the game with him.

The little girl (Anna) plays the game, but doesn't play fair. And she won't reveal the rules to Sarah Littern.

The demon so far has not revealed what the rules of the game are, or what the game is?

So what can it be?

I'm stumped. I think I have a vague idea of a direction to go in... but to be honest all I really know for sure is that it's not a "Rumplestiltskin" game.

Anyone got any suggestions?