I would go with,
The stories time period
The characters environment
And where the story takes place
Or if it is an autobiography, then you can also look at where the author is from! I hope this helps!
The character Veronica Mars is a student who progresses from high school to college while moonlighting as a private investigator under the tutelage of her detective father. In each episode, Veronica solves a different stand-alone case while working to solve a more complex mystery.
