Tense humour surrounding special plot point (5)
I believe the answer is:
twist
'plot point' is the definition.
(twist in a story)
'tense humour surrounding special' is the wordplay.
'tense' becomes 't' (grammatical abbreviation).
'humour' becomes 'wit' (synonyms).
'surrounding' is an insertion indicator.
'special' becomes 'S' (common abbreviation as in Special Air Service).
'wit' placed around 's' is 'wist'.
't'+'wist'='TWIST'
(Other definitions for twist that I've seen before include "Strong thread" , "See 14" , "Rotate; distort" , "Request for another card" , "Cheat (colloq.), dance" .)