Does pie go bad in this instalment? (7)
I believe the answer is:
episode
'this instalment?' is the definition.
(synonyms)
'does pie go bad' is the wordplay.
'go bad' indicates anagramming the letters.
'does'+'pie'='doespie'
'doespie' anagrammed gives 'EPISODE'.
'in' acts as a link.
(Other definitions for episode that I've seen before include "Story instalment" , "Chapter or event" , "Part of TV series" , "Musical passage" , "Incident in a story or part of a serial" .)