So, if you are one of these prisoners, and must only stare at the wall in front of you, you would more than likely assume the shadows of the objects are 'real.' You have never seen anything else to prove otherwise.
So Plato came up with a game.
If you could guess which shadow would appear next on the wall correctly, you would be praised and told you were clever.
The next part of the story involves an escape from the cave...
The prisoner realizes that he has been seeing the whole world incorrectly. At first, he doesn't believe it can be real.
He begins to understand, and discovers beauty and meaning. His old life and the game they played was meaningless.
The prisoner decided to come back to the cave, to tell everyone what he has found out about the world.
They don't believe him,
And threaten to kill him if he tries to set them free.
This journey that this prisoner took represents a philosophers journey when finding truth and wisdom in the world. He is the philosopher always seeking knowledge. The other prisoners are afraid of what they do not know,and do not know how to accept that they haven't been told the truth.