Anti-hero's novel being broadcast (2,3,3)
I believe the answer is:
on the air
'being broadcast' is the definition.
(I've seen this before)
'anti-hero's novel' is the wordplay.
'novel' is an anagram indicator.
'anti'+'hero'='antihero'
'antihero' anagrammed gives 'ON THE AIR'.
(Other definitions for on the air that I've seen before include "Broadcasting (hence audible)" , "Anti-hero engaged in live broadcast" , "In the process of broadcasting, radio or TV" , "radio listeners can now hear?" .)