General:
* Situation
* Circumstance
* Case
* Condition
* Possibility
* Outlook
* Prospect
* Eventuality
* Hypothesis
More specific:
* For a play or film: Act, scene, sequence, episode
* For a plan or strategy: Plan, scheme, strategy, course of action
* For a prediction: Forecast, projection, prediction, expectation
* For a fictional or hypothetical situation: Story, narrative, tale, fiction
The best alternative will depend on the specific meaning you want to convey.