Egri goes on to mention that if you intend to write a story about greed, for example, you need to know precisely what it is that you want to explore about it and what direction the story will take. Condensing your story to its premise, you have:
Greed leads to destruction, or greed leads to humiliation, or greed leads to isolation, or greed leads to loss of love.
Use the words that express your idea perfectly, knowing that it is the essence of your story. It may be brief and concise, or slightly more descriptive. Your premise should include the basic facts about the character, the conflict and its resolution.
It takes the form: Character/Subject + Conflict/Verb + Resolution/Object.
The first part of the premise should represent the dominant character trait. For example: honesty, dishonesty, selfishness, ruthlessness, false pride, etc.
The second and third parts should represent the conflict and its resolution: dishonesty leads to exposure, or, ruthless ambition leads to destruction, etc.
The premise entails a result. You, therefore, need to know the end of your story before you start to write it. This is because your premise depends on the outcome of the final conflict, typically between the protagonist and antagonist. Only then will you know if greed does indeed lead to destruction, humiliation, isolation, or loss of love in your specific story.
Finally, note that the premise encapsulates a moral aspect, which tends to dictate the kind of ending your story resolves into. In stories that resolve in an “up ending” good triumphs over evil. In a “down ending” evil tends to trump good. In the latter, your premise might well be: Greed can lead to a successful life devoid of suffering. You should be aware, however, that down endings tend to do less well in the realm of popular fiction, although there are always exceptions.
A premise contains the mortal essence or meaning of your story. It is the blueprint that informs the writing of your tale.