Story line’s not new (3)
I believe the answer is:
lie
'story' is the definition.
(story can mean a fabrication)
'line's not new' is the wordplay.
'not' is a deletion indicator.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'line' with 'n' removed is 'LIE'.
(Other definitions for lie that I've seen before include "Disinformation" , "Recline - untruth" , "Assume a horizontal position" , "Equivocate" , "found" .)