Before new scene's existence (8)
I believe the answer is:
presence
'existence' is the definition.
(I know that presence is a type of existence)
'before new scene's' is the wordplay.
'before' becomes 'pre' (prefix meaning 'before').
'new' indicates anagramming the letters.
'scene' anagrammed gives 'sence'.
'pre'+'sence'='PRESENCE'
(Other definitions for presence that I've seen before include "Impressive carriage" , "Physical attendance or imposing bearing" , "Demeanour" , "Impressive bearing" , "Being (significantly) there" .)