Complex sentence: The film noir drama, filmed and set in England, stars Alex Nicol and Hillary Brooke, who are the only Americans in the cast, although Brooke plays a British character, as she did in most films.
Split into simpler sentences: The film noir drama, filmed and set in England, stars Alex Nicol and Hillary Brooke, who are the only Americans in the cast. Brooke actually plays a British character, as she did in most films.