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' indicates an anagram (letters go or move around).
'lustre' with letters rearranged 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.)" .)