Analyze the change in Huck's character and the shift in the tone of the story with Tom Sawyer in Chapters 31-39?

Huck has developed into a more mature, morally sound individual. Huck always thought Tom's make believe adventures were not worth the time or effort Tom put into them. But, here, he believes they are truly setting Jim free, and releasing him from the bonds of slavery. For Huck, this is one of the most serious and risky actions he has ever undertaken, but for Tom, it is all just a game.