The movie title was a reference to Robert Johnson's "Crossroads" which Clapton covered in the youtube clip from my favorite song. See the boy in the movie was fascinated with Robert Johnson. The old man was a close friend to Johnson, and that is why the boy went to find him to learn more about Johnson. In the movie, the boy Eugene studied classical guitar in Julliard School, and the old man told Eugene that his blues had no soul, and that was the reason they were together to find the soul of blues. The "evil" guitarist in the movie was Steve Vai, a real life guitar hero, he did part of the music for the film.