A story is not a plot. It is not an idea. It is the answer to these six questions.
1. Who is it that is anxious?
2. What is causing them to be anxious?
3. What is their plan to relieve the anxiety?
4. What is stopping them from relieving the anxiety?
5. How do they change in order to relieve the anxiety?
6. What choice leads to that change?
Or, using more technical terms:
1. Who is the protagonist?
2. What is the nature of the instability that has made them anxious by threatening their happiness?
3. What is their chosen means for reestablishing stability?
4. What is the conflict? or Who is the antagonist?
5. How do they evolve in order to reestablish stability?
6. What options did they choose between that embodied the evolution?
In thesis form: When [character] in [stable situation] is threatened by [instability], he tries to [objective] despite [conflict] with [antagonist]. He changes from [quality A] to [quality B] by choosing [option A] over [option B].
NB: Even a writer who works by improvising can benefit by having answers to these questions in advance of starting the work. They can give the writer focus and direction while leaving many large open spaces to be filled with improvisation and inspiration.
Source: Dwight V. Swain
For more: "Storytelling Catechisms"