It follows Frank Sangster (Martin), a dentist with a successful business and perfect fiancé Jean (Dern), who one day meets an attractive but shifty new patient, Susan (Bonham-Carter). Susan asks Frank for a not-entirely-legal pain medication prescription, and not long after, his life begins a downward spiral of lies and conspiracies.
Novocaine contains examples of
- Betty and Veronica: Jean, Frank's demure, rules-conscious fiancee, is the Betty, and Susan, the seductive, manipulative drug-addict is the Veronica. Except the roles turn out to be inverted; Susan is revealed to actually be a broken but ultimately good-hearted woman trapped in her life by her abusive brother, while Jean is actually a scheming, manipulative Femme Fatale planning to frame Frank for murder and steal his business.
- BrotherSister Incest: A rather disturbing example with Susan's brother, who demonstrates a blatant sexual (albeit drug-addled) attraction to her.
- The Cameo: An uncredited Kevin Bacon has two small scenes as an actor researching an upcoming role.
- Chekhov's Armoury: Pretty much everything mentioned in the first five minutes comes full circle by the end.
- Domestic Abuse: Susan's first appearance has her with a bruise on her face, and later she has a bloody nose from her brother.
- Eureka Moment: Frank sees a commercial for denture cement, and suddenly it becomes clear that everything that has happened is part of a plot by Jean to take over his business (He remembered that she was practicing making dentures earlier, and that a cast of his own teeth were made).
- Femme Fatale: Susan, a mysterious and manipulative woman who leads a man who becomes heavily attracted to her into a world of trouble. Except that Susan actually turns out to be fairly good-hearted and trapped in a miserable life herself, and it's actually Jean who's the real Femme Fatale.
- Pretty Little Headshots: Apparently a face full of buckshot is a hell of a lot cleaner than you'd normally expect.
- The Tooth Hurts: To be expected from a black comedy thriller centered around a dentist. In the climax, Frank fakes his death by ripping out all his teeth and that of his deceased brother Harlan, and placing his teeth into Harlan's mouth, and finally burning down the building.