Take the popular Disney movie "Moana" for example.  If you altered the setting, in this case time, in the movie Moana from the past to the present, the whole storyline would be affected.  One way this shows is if you change the time period, Moana wouldn't have to make the journey across the open ocean in a small rowboat.  She can now take a faster type of boat, or even an airplane.  Moana wouldn't even need to make the journey at all if the time period was changed.  She would be able to text or call Maui and demand him to return the heart.  She could ship the heart to Maui through a mail company.   Changing the time period can change the how the entire plot unfolds, as the movie "Moana" shows.  

In the comments, give me ways that you think other movies are affected if you change a small detail; the setting.