Conspiracy story (4)
I believe the answer is:
plot
I believe this clue is a double definition.
'conspiracy' is the first definition.
(I know that conspiracy can be written as plot)
'story' is the second definition.
(I know that story can be written as plot)
(Other definitions for plot that I've seen before include "Make map" , "Patch of ground" , "Concoct schemes" , "See 12 Across" , "Secret scheme to do something underhand" .)