Complex sentence: The story line, which did in fact receive the sought after MPAA "R" rating, is about a single eventful night in the lives of a crew of L.A. based, trans-Pacific stewardesses.
Split into simpler sentences: The story line which, did in fact receive the sought after MPAA "R" rating. The movie is about a single eventful night in the lives of a crew of L.A. based, trans-Pacific stewardesses.