John is cursed and must kill anything that comes near a pool of water he sits in. On finally being captured he is locked up in a cage in the kingdom. The giant isn't even put on trial or questioned about why he was killing people. He is seen as a trolling monster who needs to be locked up. With the king's son we see the other side of Iron John; he may be iron but he has a heart of gold.
The boy is left to watch that nothing falls into a golden stream. Because he has the playfulness of a child he ends up with a golden finger and golden hair. John is disappointed that the prince could not keep his end of the deal. The giant sends him out of the forest telling him he must live poor for the rest of his life. If he ever needs anything he can return to the forest and iron John will help him. The giant is the self-proclaimed richest man in all the land.
Eventually a war breaks out. The boy is now a man willing to fight in the battles. Most in the kingdom tease him about his want to go to war. They leave an old broken down horse in the stable for him to ride. The Prince goes to Iron John for help, in return he gets a horse, armor, and his own army. Since he lives modestly now he returns what was given to him. This is a good move, he needs it a little time later to win over the princess' hand in marriage.