Rubbish in plot upset gentleman turning up (6)
I believe the answer is:
debris
'rubbish' is the definition.
(debris is a kind of rubbish)
'plot upset gentleman turning up' is the wordplay.
'plot' becomes 'bed' (bed is a kind of plot).
'upset' is a reversal indicator.
'gentleman' becomes 'sir' (I've seen this before).
'turning up' shows that the letters should be reversed in order.
'bed' in reverse letter order is 'deb'.
'sir' backwards is 'ris'.
'deb'+'ris'='DEBRIS'
'in' is the link.
(Other definitions for debris that I've seen before include "Broken remains" , "Rubble, heap of broken pieces" , "Detritus, rubbish" , "Refuse remains" , "Fragments of rubbish" .)