Subject, say, featuring in story (5)
I believe the answer is:
liege
'subject' is the definition.
(thesaurus)
'say featuring in story' is the wordplay.
'say' becomes 'eg'.
'featuring in' means one lot of letters goes inside another.
'story' becomes 'lie' (I've seen this before).
'eg' going within 'lie' is 'LIEGE'.
(Other definitions for liege that I've seen before include "European university" , "Vassal, subject" , "Feudal vassal from a Belgian city" , "European city" , "old lord" .)