Recount story that's revealing (8)
I believe the answer is:
telltale
'that's revealing' is the definition.
(synonyms)
'recount story' is the wordplay.
'recount' becomes 'tell' (synonyms).
'story' becomes 'Tale' (synonyms).
'tell'+'tale'='TELLTALE'
(Other definitions for telltale that I've seen before include "Revealer of secrets" , "Revelatory - blabbermouth" , "Person who blabs, or something revealing" , "Blabbermouth, snitch" , "Blabber-mouth, can't keep a secret" .)