Behind the prisoners

Behind the prisoners, there is a fire, and between the fire and the prisoners, there is a parapet along which puppeteers can walk. The puppeteers, who are behind the prisoners, cast shadows on the wall of the cave by holding up various objects in front of the fire.
The prisoners see these shadows and believe them to be the only reality since they have never seen anything else.
The Escape:

One of the prisoners is freed and is initially blinded by the light. Gradually, he comes to see the fire and the objects casting the shadows, realizing that the shadows on the wall are not reality but mere reflections of the true forms.