Conspiracy in bed? (4)
I believe the answer is:
plot
I believe this is a double definition.
'conspiracy' is the first definition.
(I've seen this before)
'bed?' is the second definition.
(I've seen this before)
'in' acts as a link.
(Other definitions for plot that I've seen before include "Mark position" , "bed" , "The story told in a novel" , "Graph; piece of ground" , "Connive" .)