Davis plays Judith Traherne, a carefree, hard-partying, rich Long Island socialite who becomes less carefree when she starts suffering from headaches, blurred vision, and dizziness. Pressured by Ann, her secretary/assistant (Geraldine Fitzgerald), Judith finally goes to see neurosurgeon Dr. Frederick Steele (Brent). Dr. Steele diagnoses Judith with a brain tumor and performs surgery. Unfortunately the surgery, while relieving the symptoms that sent Judith to the doctor, fails to cure her condition, leaving her with less than a year to live. Dr. Sterne and Ann decide not to tell Judith about her diagnosis. Meanwhile, Judith and Dr. Steele fall in love.
Dark Victory was a critical and commercial hit for Davis and Warner Bros. Humphrey Bogart, playing Michael, the manager of Judith's stable of horses, is billed third. Bogart had been a character actor for years with Warner, and would not break out as a star until High Sierra and The Maltese Falcon in 1941. Even more interestingly, none other than future President Ronald Reagan is billed fifth, playing Alec, one of Judith's Long Island society pals. This part was an early-career highlight for Reagan, who spent most of his time at Warner Bros. in B-movies.
This film provides examples of:
- The Alcoholic: Alec (who, to repeat, is played by Ronald Reagan) is drinking, drunk, or hung over in every single one of his scenes.
- Altar the Speed: Judith basically asks Dr. Steele to marry her, saying she wants a wedding and happiness before she croaks.
- The Disease That Shall Not Be Named: A very weird example. Dr. Steele calls Judith's problem a "glioma" (a medical term for a malignant brain tumor) and a "growth", and even uses the word "malignant" once. The word "cancer" is never uttered in the movie.
- Driving a Desk: A particularly bad example when Judith and Ann are driving out to the stables.
- Everybody Smokes: Judith smokes in the hospital, in her bed as she waits to go under the knife for brain surgery.
- Exact Words: "I think I can promise a complete surgical recovery", says Dr. Steele, who doesn't want to tell Judith that the surgery failed to stop her brain cancer.
- Face Death with Dignity: The filmic Trope Codifier. "Is that you, Martha? I don't wish to be disturbed."
- Idle Rich: Judith, Alec, and their peers in the Long Island smart set, who seem to have a lot of time to drink, party, and ride horses.
- Ill Girl: Judith, whose terminal brain cancer drives the plot.
- Impairment Shot: Judith's vision blurs, causing her to miss a jump while riding her horse.
- Locked Out of the Loop: Ann and Dr. Steele decide not to tell Judith that the surgery failed. She is none too happy when she finds out.
- Ooh, Me Accent's Slipping: Michael is supposed to be Irish. It's hard to tell, because Bogart delivers what might be the worst Irish accent in the history of the world.
- The Remake: A 1976 Made-for-TV Movie version starred Elizabeth Montgomery (of Bewitched fame) as an updated version of the protagonist, now named "Katherine Merrill" and employed as a television producer. Anthony Hopkins played her doctor and love interest, Steele.
- Title Drop: Judith says of her happiness with Dr. Steele that "that's our victory, our victory over the dark."
- Victorian Novel Disease: Weirdly both averted and played straight. Judith has at least a somewhat realistic set of symptoms—numbness, headaches, blurred vision, dizziness, mental confusion. But after her surgery she has some kind of Hollywood Brain Cancer that leaves her feeling perfectly healthy, and looking beautiful, until the attack of blindness that means death is just hours (not weeks or days, but hours) away.
- Your Days Are Numbered: Judith has to live through this trope after finding out the truth about her condition. She resolves to grab what happiness she can.