Complex sentence: John Finley Horton (James Whitmore) is a white journalist who artificially darkens his skin and passes for a black man in the deep South, from New Orleans to Atlanta, where he encounters racism from both white and black people.
Split into simpler sentences: John Finley Horton (James Whitmore) is a white journalist who artificially darkens his skin in order to pass for a black man. He spends time in places from New Orleans to Atlanta, and encounters racism from both white and black people.