Coming across short story about party-goers (9)
I believe the answer is:
traversal
'coming across' is the definition.
(travelling across something)
'short story about party-goers' is the wordplay.
'short' means to remove the last letter.
'story' becomes 'tale' (synonyms).
'about' is an insertion indicator.
'party-goers' becomes 'ravers'.
'tale' with its last letter removed is 'tal'.
'tal' enclosing 'ravers' is 'TRAVERSAL'.
(Other definitions for traversal that I've seen before include "Act of crossing" , "A crossing (of something)" , "Action of crossing" , "A journey across" , "crossing over bridge" .)