The film is set in a galaxy far, far away, where a young farm boy named Luke Skywalker (Mark Hamill) dreams of adventure beyond his desert planet, Tatooine . Luke stumbles upon a message from Princess Leia Organa (Carrie Fisher) hidden in the droid R2-D2 , which leads him to Obi-Wan Kenobi (Alec Guinness), an old Jedi Knight. Obi-Wan presents Luke with his father's lightsaber and begins to teach him the ways of the Force .