premise: Nymphomaniac (film) is the third installment of a tetralogy.
hypothesis: Nymphomaniac (film) . Nymphomaniac is the third and final installment in von Trier 's unofficially titled `` Depression Trilogy '' , having been preceded by Antichrist and Melancholia . The Twilight Saga is a series of five romance fantasy films from Summit Entertainment based on the four novels by American author Stephenie Meyer .