"The Music Man" setting (4)
I believe the answer is:
iowa
'the music man setting' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for iowa that I've seen before include "US state, three vowels" , "American state, capital Des Moines" , "US swing electoral state" , "part of US" , "State of USA" .)