So what is preview flashback structure? Preview flashback structure is when a scene taken from the end of the film is placed at the start, after which the film then jumps back to its disturbance (how the story started) and continues uninterrupted until its end. So the opening scene acts like a teaser, or preview. The scene chosen to be seen first (the 'preview' scene) is usually the climax or second act turning point of the story (because these are so inherently dramatic they easily grab the audience), but sometimes other dramatic high points are used (you'll need to check out my book The 21st Century Screenplay for details - no room here). The movie Michael Clayton uses a preview flashback, by the way.
Dear Linda, I wanted to ask you a quick question about preview flashbacks. Do I need to continue the preview scene which I start the film with at the end or could I finish the story right after I connect it to what I have shown in the beginning?
It’s very hard to give an answer about a script that I haven’t seen and unfortunately I don’t have the time to read your script. However, there’s no reason why your short film shouldn’t end right after the return of the opening scene,. However, be careful that the ending is striking enough to end the film with impact. You may have to add an ironic twist – a ‘Rosebud’ twist, as I explained in the seminar. This is to avoid an anticlimax or ‘fizzer’ when you repeat the scene. Mostly, when the opening scene of a film is actually the climax, people do insert an ironic twist. So think carefully about whether you need an ironic twist or not.
I'd add here that, obviously, the preview scene would need to be from the last part of the film for this to work. The return of the opening scene would need to provide pleasing closure.