Whenever you tell a story, you make an implicit contract with the reader. Within the first few paragraphs or pages, you tell the reader implicitly what kind of story this is going to be; the reader then knows what to expect, and holds the thread of that structure throughout the tale. . . .

The rule of thumb is this: Readers will expect a story to end when the first major source of structural tension is resolved. If the story begins as an idea story, the reader expects it to end when the idea is discovered, the plan unfolded. If the story begins as a milieu story, the readers will gladly follow any number of story lines of every type, letting them be resolved here and there as needed, continuing to read in order to discover more of the milieu. A story that begins with a character in an intolerable situation will not feel finished until the character is fully content or finally resigned. A story that begins with an unbalanced world will not end until the world is balanced, justified, reordered, healed—or utterly destroyed beyond hope of restoration.

It’s as if you begin the story by pushing a boulder off the top of a hill. No matter what else happens before the end of the story, the reader will not be satisfied until the boulder comes to rest somewhere.

Card, Orson Scott. Characters and Viewpoint (Elements of Fiction Writing). Cincinnati, OH: Writer’s Digest Books, 1988. 54–55. Print.