Plato's Allegory of the Cave is a philosophical metaphor found in his work 'The Republic,' illustrating the difference between the world of appearances and the world of reality. In this allegory, prisoners are chained inside a cave, only able to see shadows cast on a wall by objects behind them, which represent perceptions based on limited experience. The journey of one prisoner who escapes and discovers the outside world symbolizes the process of self-discovery and enlightenment, connecting deeply to themes of identity and understanding one's true self.