In 1928, when Martha Smith Ivers (Janis Wilson) was a teenager, she accidentally killed her rich, domineering aunt (Judith Anderson) by knocking her down the stairs after the aunt got angry with her for trying to run away with Sam Masterson (Darryl Hickman). The only witness to the killing was her tutor's son, Walter O'Neil (Mickey Kuhn). Eighteen (18) years later, Martha (Barbara Stanwyck) has inherited her aunt's fortune, built up a successful business empire, and she and Walter (Kirk Douglas), now a successful district attorney, are married. When Sam (Van Heflin) has an accident passing through Iverstown and must stick around until his car is fixed, Walter and Martha suspect that he's there to blackmail them, while Martha wants to get back together with Sam. However, Sam has linked up with Antonia 'Toni' Marachek (Lizabeth Scott), a beautiful blonde with a not-so-beautiful past. All of their pasts come together with tragic results.

The movie is based on a short story, 'Love Lies Bleeding' by American playwright John Patrick. The short story was adapted for the movie by American screenwriters Robert Rossen and Robert Riskin.

Martha's kitten ran down the stairs. Her aunt, who hated the cat, beat it to death with her cane. When Martha saw her beating the kitten, she grabbed the cane from her aunt's hand and hit her with it...just once...but it caused the aunt to fall down the stairs. The aunt died instantly from the fall.

Martha's aunt (Mrs Ivers) was the sister-in-law of Martha's mother, a born Ivers. The sister-in-law married a man named Smith, hence Martha Smith. When Martha's mother died, her aunt had Martha's last name legally changed to Ivers, as she was the sole heir to the Ivers' fortune.

Martha's "strange love" refers to the neurotic love that has grown out of her feelings of emptiness. This need for love has led her to have a long series of lovers. Walter lists them off for Sam, a gymnasium instructor in Philadelphia with a muscle for a brain and tendency to insipid verse [...] a guy named Pete in Erie who smells of fish and sings [...] last year's greatest fullback [who] flunked [his] bar exam but [...] wanted to be an industrial engineer [...] a guy who came along to fix a tire so well [he] became a city-paid inspector. When Sam returns to Iverstown, Martha doesn't even recognize his name at first. However, once she realizes who he is, she becomes certain that he is the one man she has always dreamed about, the one man who can fill that emptiness in her. It refers also to the "strange love" she shares with her husband. Throughout the film, she wants only to get away from him but, when she feels betrayed by Sam, she fears that Walter will no longer stand by her.

When Sam carries Walter into his room and lays him in a chair instead of killing while he's unconscious, Martha feels betrayed. "I thought you loved me", she says. "I dreamed of you coming back." Sam simply tells her that she's sick and that her whole life has been a dream. As Sam tends to Walter, Martha stealthily removes the gun from Walter's desk drawer. When Walter comes to, she points the gun at Sam and tries to get Walter to agree to back up her story that she shot Sam in self-defense, but Walter says nothing. Sam turns his back on Martha and walks out of the room. Martha drops the gun, and Walter pockets it. As Martha watches Sam walk away from the house, Walter embraces his wife and assures her that he won't leave her. He then points the gun at her abdomen. "You believe me", Martha says confidently, then puts her thumb through the trigger ring over Walter's thumb and presses it, shooting herself. A voice is heard calling, "Ivers...Ivers", but Martha says, "No...Smith", and falls to the floor. Sam hears the shot and runs back to look in the window. He sees Walter turn the gun on himself, and another shot rings out. Sam continues to walk away, returning to his hotel room where he finds Toni has returned and is waiting for him. "I missed a bus once and I was lucky", she explains. "I wanted to see if I could be lucky twice." In the final scene, Sam and Toni are leaving Iverstown. Toni turns to look back, but Sam warns her not to. "Remember what happened to Lot's wife." he says. "Whose wife?", Toni asks. "Sam's wife", Sam replies.

A biblical story in Genesis Ch.19 tells how Lot and his family were allowed to flee the city of Sodom before the Lord destroyed it, but they were warned not to look back. Lot obeyed and got safely away, but his wife disobeyed, looked back, and was turned into a pillar of salt. The story is a thinly-veiled reference to the fates of Sam and Martha. Martha 'looked back' and coveted her early years with Sam and was ultimately destroyed by it. Sam refused to 'look back' and lived.