Fred MacMurray is cast against type as insurance peddler Walter Neff. Neff is a little too sure of himself, and thinks he knows all the angles. He visits a client at his home, but instead meets his wife Phyllis Dietrichson (Barbara Stanwyck). Stanwyck soon realizes that MacMurray is stuck on her, and that this is a golden opportunity for her to rid of her hated husband, who shows no interest in her. Stanwyck presses MacMurray for accident insurance on her husband, and drops hints of murder as she bats her eyes at him.

Throughout the movie, Stanwyck's character is evil incarnate. She has murdered before, and plans to again. She has no feelings, but can act any emotion required to get what she wants. Soon MacMurray has been reeled in completely, and schemes to kill the unlucky husband to collect a $50,000 insurance policy.

To collect double the policy amount, Stanwyck's husband must be killed in a train accident. Stanwyck and MacMurray kill him, MacMurray impersonates the husband on the train, and once alone, jumps off the train. The body is then placed on the tracks by the murderous couple.

MacMurray's boss Norton is suspicious of the "accident", suspecting suicide. Claims adjuster Barton Keyes (Edward G. Robinson) suspects murder. Fortunately for MacMurray, Robinson is a long time co-worker and confidant, and he does not suspect him.

Edward G. Robinson was one of the all-time great character actors. He did not have the looks or voice of a leading man, but he had sufficient charisma to get leading roles anyway, usually as a crime boss. On an occasion when he had a leading man role, he played the love-blinded sap as in "Scarlet Street".

Robinson does a great job as Barton Keyes, scowling, growling, and suspicious of everything. He suspects that MacMurray's imaginary girlfriend Marjorie drinks from the bottle. Keyes was once engaged, but then suspected his girlfriend. He had her investigated, then broke the engagement! He always has a two-for-a-quarter cigar in his hand, but can never find a match. Perhaps that is why he enjoys MacMurray's company, as he constantly lights his cigars for him.

The script, co-written by director Billy Wilder and crime novelist Raymond Chandler, is terrific. The direction is excellent as well and milks the inherent suspense from every scene. Many times, MacMurray or Stanwyck are on the verge of having their evil plan collapse, but survive after much dramatic tension.

Oh, and there's also a needless romance between MacMurray and Stanwyck's doe-eyed daughter-in-law Lola (Jean Heather). And MacMurray's character has an unlikely change of heart at the end. But few movies are perfect!