Horror story and awful gripe about messenger (7,6)
I believe the answer is:
carrier pigeon
'messenger' is the definition.
(I've seen this before)
'horror story and awful gripe about' is the wordplay.
'horror story' becomes 'carrie' (I can't explain this - if you can you should believe this answer much more).
'and' says to put letters next to each other.
'awful' indicates an anagram.
'about' becomes 'on' (a book about x is on x).
'gripe' anagrammed gives 'rpige'.
'carrie'+'rpige'+'on'='CARRIER-PIGEON'
Can you help me to learn more?
(Other definitions for carrier pigeon that I've seen before include "Avian messenger" , "Bird with message" , "Bird taking messages" , "Bird used for communication" , "Aerial messenger" .)