I keep six honest serving-men
(They taught me all I knew);
Their names are What and Why and When
And How and Where and Who.
Those six one-word questions are the basis of any story. What is happening, where and when is it happening, to whom is it happening, why is it happening, and how are we going to solve the problem?
Certain things are going to be hidden based on the genre. A romance might have all those aspects right up front, except for the last. Because it's HEA or HEAFN (Happily ever after or Happily ever after for now) all of the other information can be right out in plain sight. For a mystery of any kind, the why and who (as in who is doing this) are likely to be hidden.
Where and when are generally pretty obvious, and in science fiction or fantasy they may be extremely important to the story as a whole. In other genres the why may be hidden while everything else is clear. In almost every case, though, the how remains out of sight.
Humans are wondering creatures. We want secrets and unknowns, even in our entertainment. If there are no secrets, we're likely to put the book down or go to sleep during the movie. So while you need all six questions in your story, it's possible to minimize or hide some to keep your readers reading.
Think about a story with no setting. Boooooring. Think about a story with no characters--even stories about a mountain or a city personify those things and turn them into characters.
If you're missing any of those aspects, your story is likely to fall flat with your readers.
That doesn't mean you can't mix it up. Your where can be spread out over six different timezones, or take place in twenty different solar systems. Your when can skip back and forth between times, or not have a set "time." That's OK, if it's done well. But you must have each of those six items.
On the other hand, writing without one can be an interesting exercise. Try it. Try writing a short story without any characters, or without a "how" and see if you can do it. "Why" is probably the easiest to dispense with, followed by "how." Can you make the story make sense without at least suggesting that there is a why to the plot?
Try it. If you manage it, let me know.