Plot sketch
The primary purposes of a plot sketch include:
Helps writers to see the "big picture" of their story and organize their thoughts and major plot points in a clear, visual way.
Ensures the narrative has a clear beginning, middle, and end, and that the events follow a cause-and-effect relationship.
Makes it easier to spot plot holes, weak points, or inconsistencies in the storyline that might otherwise be missed until later stages of writing.
Allows writers to plan how tension will build to a climax and then decrease toward a resolution, ensuring the story is engaging and well-paced.