It's Fred MacMurray again, as a virtuous agent for the causes of good. Instead of playing an insurance salesman with an eye for the fast buck, here he's playing a cop assigned to shadow Novak, the mobster's moll. Kim Novak is as beautiful as she's ever appeared on the screen. The lighting in her early scenes is as dramatic and sensual as it can be. Who wouldn't fall in love with her? Comparisons with Double Indemnity just can't be ignored. She is the vamp that Barbara Stanwyck could never be. She's softer and more feminine in that 50's style, and less hard-edged than Stanwyck, which makes her much more dangerous. Novak's generally wooden acting style & "flat affect" gives way to a softer sex-kitten demeanor. MacMurray's character is a more active participant in the events that unfold than in "DD", where he seemed to get his courage and strength from Stanwyck's cold & calculating personna. Billy Wilder could have made this a masterpiece, but even without the guidance of the master's hand, this one is definitely well-worth watching.