Every story ever told follows the same basic formula known as the three-act structure, and movie trailers are no exception. The three acts are labeled setup, confrontation and resolution, and each contain key plot points that drive a story forward. Movie trailers usually contain all but one key plot point, the falling action. If trailers revealed elements from the film’s falling action then, obviously, the plot would be spoiled.
The setup of a plot usually begins with an introduction to the main protagonist and the world they live in. It is then followed by the inciting incident. The inciting incident, also known as the point of no return, is the moment in the film when the main character must embark on their journey. This leads into the confrontation which includes the rising action. The stakes are raised higher and higher, building tension. The character must face a series of increasingly difficult obstacles in order to try and relieve that tension. This leads to the crisis or climax of the film where the protagonist must face their destiny.
Take the trailer for the 007 film Casino Royale:
It begins with the protagonist (Bond, James Bond) killing a man who is lecturing him about killing. Immediately, we know our hero is a bad-ass super spy. We are then introduced to the film’s villain, a banker for international terrorists. He is holding a poker tournament in Montenegro and it’s up to Bond to stop him. Bond accepts the mission marking the inciting incident. Bond’s first obstacle is to win over the woman providing him with his gambling money. He needs to prove to her that he is trustworthy and capable of taking on the mission. In classic Bond fashion they fall in love, and she becomes a target of the villain. Her kidnapping leads to the climax of the trailer: Bond fighting to rescue her. And, of course, we are left to wonder if he actually manages to save the day.
Because film trailers are essentially advertisements, creating them with this structure really helps to increase the film’s marketability. Audiences want to know what they are going to spend their money to see. Providing us with a micro-film is just enough to get us to buy tickets even if it’s only to see the final part of the three-act structure.