Save the Cat: The Last Book on Screenwriting You'll Ever Need

The logline is a movie’s one- or two-sentence description of what it’s about. According to the author, a potent logline reveals some irony and conflict, as well as providing a brief description of the hero. It should also hint at the target audience and potential cost.

Beats are individual scenes in a movie or story. Each beat should feature a conflict and a change in the emotional tone. In the BS2, Snyder allows for 40 beats spread over three acts.

Snyder uses these terms to label the three acts of a screenplay and their function. Act 1, the thesis, should introduce the hero and the other important characters, as well as set up the premise. Act 2, the antithesis, plunges the hero into a new world or turns the hero’s world or expectations on end. Act 3, the synthesis, shows the results of the hero’s actions and growth, metaphorically creating a new world.