Second film in the Pink Panther franchise (1,4,2,3,4)
I believe the answer is:
a shot in the dark
(Other definitions for a shot in the dark that I've seen before include "made by night-time assassin" , "what a night sight's for?" , "this could suggest a midnight murder" , "Random guess, wild speculation (1,4,2,3,4)" , "Wild stab" .)