In The Starlite Drive-in, it’s posited in the first paragraph:
“I wasn’t there when they dug up the bones at the old drive-in theater, but I heard about them within the hour. In a small town, word travels like heat lightning across a parched summer sky. Irma Schmidt phoned Aunt Bliss and delivered the news with such volume that her voice carried across the kitchen to where I was sitting.”
The central dramatic question is “Whose bones are in that grave?” It isn’t until the last chapter that the reader learns who was murdered and why.
In Shirley Jackson's novel, The Haunting of Hill House, the CDQ is also immediately clear:
“No live organism can continue for long to exist sanely under conditions of absolute re-ality; even larks and katydids are supposed, by some, to dream. Hill House, not sane, stood by itself against its hills, holding darkness within; it had stood so for eighty years and might stand for eighty more. Within, walls continued upright, bricks met neatly, walls were firm, and doors were sensibly shut; silence lay steadily against the wood and stone of Hill House, and whatever walked there, walked alone.”
Just that one paragraph prompts the question: What terrible things are going to happen in that creepy house, perhaps a murder?
In C.S. Forester’s novel, The African Queen, the CDQ isn’t clear until Chapter 2 when Rose Sayer, a spinster whose missionary brother has just died, meets up with Charlie Allnut, a cockney ne'er-do-well who happens to possess a dilapidated thirty-foot boat, The African Queen. Rosie and Charlie are co-protagonists, and a novel could not have two more opposite characters. With difficulty, Rosie per-suades the very reluctant Allnutt to take the boat several hundred miles down Africa’s Ulanga River with the goal of torpedoing a German war ship, the Louisa. It’s a noble goal but nearly impossible for two people to accomplish. At that point, the central dramatic question becomes, “Will Rosie and Charlie manage to blow up the Louisa?”
The reason the CDQ is important is because it quickly tells your reader what the story is going to be about. It's different from the theme (the novel's underlying meaning) and from the premise (the author's position on the theme). For example, The Starlite Drive-in's theme is entrapment, and the premise is that love can free the human spirit. Those are different from the book's CDQ (Whose bones are in that grave?).
If you've ever read a novel that makes you question "Where is this story going?" it's likely the author hasn't made the CDQ clear—or maybe he doesn't have one. Don't wait too long to introduce the CDQ because, unless you have some strong action or some smaller questions early on, the reader is likely to lose interest.
A good novel has story questions all through it but at least one big question should stand out and must be answered by the end. If you answer it midway through the novel or earlier, you must present another important CDQ and answer it by the end.
Think about your manuscript. Does it have a CDQ? If you have a strong one, have you made sure you've created plot points that will lead to a definitive answer? Have you answered all the other questions you've introduced along the way? That's known as "tying up loose ends."
As an exercise, write down your central dramatic question and consider how it has helped—or could help you plot your novel.