A woman named Danielle (Margot Kidder) leads a man named Philip (Lisle Wilson) back to her apartment, apparently for sex; however, when Danielle steps into an adjoining room, Philip overhears an argument. Danielle is now distraught. She says she was arguing with her twin sister. It's their birthday. Philip excuses himself and comes back minutes later with a surprise birthday cake.

A young Staten Island journalist, Grace Collier (Jennifer Salt), in the apartment building that faces Danielle's, witnesses what happens next: the birthday girl grabs the knife to cut the cake and instead critically stabs Philip.

Grace calls the police, though her credibility with the men in blue is in doubt because she has written several highly-critical editorials of the police department. Two officers arrive, and Grace escorts them to the scene of the crime. But by the time they arrive, however, all evidence of the murder has disappeared.

DePalma brilliantly utilizes the inherently gimmicky split-screen process (a very non-Hitchcockian technique) for much of this sequence. As Grace and the police first argue and then ride the elevator, the split-screen process shows us Danielle and her husband Emil (William Finley) cleaning up the mess and disposing of Philip’s body. The split-screen process is integral to this sequence, and DePalma films most of it in silence, except for Bernard Herrmann’s score, so as not to disorient the viewer with overlapping dialogue.

Sisters plays with issues of duality and perception: Danielle has power struggles with Dominique; Danielle argues with Emil; and most importantly, a link between Danielle and Grace is suggested. Danielle and Grace are both treated condescendingly by men –- Grace and the police; Danielle and Emil; and Grace and Emil.

It’s interesting to note that the one man who doesn’t treat Danielle condescendingly ends up brutally murdered. This undoubtedly stems from Philip being a black man and the condescending attitudes that he encounters daily. In the movie's opening sequence, Philip takes Danielle out on a date with gift certificates he won from a television show. The gift certificates are for dinner at a restaurant called The African Room, where the black waiters wear grass skirts, dress shirts, and black top hats. Philip silently submits to the broad racial caricatures.

The restaurant scene is inspired in its social criticism. But whatever social commentary DePalma manages to slip into the film never detracts from the narrative. He doesn’t have the time. Sisters is so tightly wound and lacking in filler that to deviate from the more prominent concerns would have lessened the film’s immediacy.

The last act of the film, when Grace follows Emil and Danielle back to Emil’s mental clinic, goes right off the rails and into the grand guignol. Grace’s hallucination/revelation of the events that tie her to Danielle and Emil is a memorable and sickly humorous descent into madness. The scene comes off like a free-for-all between Bunuel, Fellini, and Guy Maddin.

Sisters was made by a director in complete control. Yet the film has breathing room; its characters never come across as stiff or one-dimensional, especially the female leads. It’s a shame that DePalma would rarely be this insightful again.

The Criterion Collection has released Sisters in a widescreen format (1.85:1). Though the disc would have benefitted from a director’s commentary, the DVD does include an interesting interview with DePalma from 1973 on the making of the film and an essay by DePalma for the Village Voice on working with famed composer Bernard Herrmann (a frequent Hitchcock collaborator who wrote the score for Vertigo, North by Northwest, and Psycho). The disc also includes hundreds of production, publicity, and behind-the-scenes stills, as well as excerpts from the original press book.