Lustre going off in sequel (6)
I believe the answer is:
result
'sequel' is the definition.
(thesaurus)
'lustre going off' is the wordplay.
'going off' is an anagram indicator (letters go or move around).
'lustre' anagrammed gives 'RESULT'.
'in' is the link.
(Other definitions for result that I've seen before include "Ulster (anag) - outcome" , "Effect of lustre" , "'Outcome, upshot (6)'" , "Verdict" , "Rustle (anag.)" .)