B movie opening and closing cinema presentation to create mood (8)
I believe the answer is:
ambience
'mood' is the definition.
(I know that ambience is a type of mood)
I don't understand how the remainder of the clue works.
(Other definitions for ambience that I've seen before include "Aura (of a place)" , "Surrounding influence" , "Mood of place" , "Surroundings or atmosphere" , "Character and atmosphere of a place" .)