The Just Man

Once upon a time there lived a little heart in the chest of a just man. This man was good and full of mercy.
But the little heart wanted to get to know the world and so one day it set out into the world.
It jumped out of the man's chest and moved away.
But now this just man had no heart any more and he became cruel and emotionally cold. People began to be afraid of him.
Meanwhile, the heart was on a journey around the world. Innocent as it was, it believed only in the good, never had it had to experience atrocities. But from then on out in the big wide world it found only evil.
Bad hearts made his acquaintance. It taught them its virtues and tried to change the bad hearts.
Will the heart make it?
Will it ever return to the just man's chest?
And what happens to this man?
Will he remain heartless forever?