Complex sentence: Rochefort is set to appear in the second series of The Musketeers played by Marc Warren where he will replace Cardinal Richelieu (Peter Capaldi) as the show's antagonist.
Split into simpler sentences: Rochefort is set to appear in the second series of "The Musketeers" played by Marc Warren. He will replace Cardinal Richelieu (Peter Capaldi) as the show's antagonist.