Deceptive plan (4)
I believe the answer is:
ruse
'deceptive plan' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ruse that I've seen before include "Cunning scheme" , "Subterfuge" , "Sure its a strange deception" , "Deceptive tactic" , "Sure to be a trick" .)