Cronies upset about a storyline (8)
I believe the answer is:
scenario
'storyline' is the definition.
(I've seen this before)
'cronies upset about a' is the wordplay.
'upset' is an anagram indicator.
'about' indicates putting letters inside.
'cronies' with letters rearranged gives 'scenrio'.
'scenrio' placed around 'a' is 'SCENARIO'.
(Other definitions for scenario that I've seen before include "Imagined sequence" , "Film/novel plot outline" , "Dramatic set-up" , "Outlines of drama" , "In plot of movie, for instance" .)