1972’s Sisters begins by introducing us to a likable ad executive named Philip Woode (Lisle Wilson). Woode is the victim of a prank show and, for his trouble, he wins dinner for two at a nice Manhattan restaurant. Daniele Breton (Margot Kidder), the model/actress who set him up for the show, agrees to be his date. They have a lovely night that ends at Daniele’s apartment. In the morning, Daniele explains that it’s not only her birthday but also the birthday of her twin, Dominique. Philip, being a nice guy, goes not only to refill Daniele’s prescription but also to pick up a birthday cake. He then comes back to the apartment and, in true Psycho fashion, is promptly stabbed to death by one of the sisters.

Across the street, journalist Grace Collier (Jennifer Salt) looks out her window just in time to see Philip getting stabbed and then using his own blood to write “help” on the apartment window. Director Brian De Palma makes good use of his trademark split-screen technique. On one side of the screen, we watch Philip dying. On the other side, we explore Grace’s apartment and see that, in the past, she’s written an editorial headlined “Why We Call Them Pigs.” We know that Grace is the only person who has witnessed Philip’s murder, and we also know why the police are not going to be inclined to believe her.

And indeed, by the time the police arrive, Daniele and her creepy ex-husband, Emil (William Finley), have already hidden Philip’s body in a couch. With the police proving to be of no help, Grace hires a private detective named Joseph Larch (Charles Durning) to break into Daniele’s apartment and search for clues. Durning doesn’t have a huge role in Sisters, but he definitely makes an impression as he proceeds to follow that couch across the country. De Palma’s dark sense of humor is evident as the couch eventually ends up in the wilds of Canada, where Durning uses his binoculars to keep an eye on it.

Sisters was an early De Palma film, one that gives him a chance to show off both his ability to generate suspense and the style that would become his trademark. It’s an effective film, one that has a plot that is full of twists but which can still easily be followed by the audience. Indeed, I doubt anyone will be shocked to discover the truth about Daniele and Dominique, but Margot Kidder gives such a good performance and De Palma directs with such confidence that the story still holds your attention. As for Jennifer Salt, she’s playing the type of radical journalist who probably would have identified with the politics of Greetings and Hi, Mom! while ultimately rejecting both films for their casual misogyny. It undoubtedly says something about De Palma’s worldview that, while he obviously sympathized with Grace’s politics, he still ultimately portrayed her as being an ineffectual investigator.

In the end, Grace is as much of a sister to Daniele as Dominique is. They’ve found themselves being manipulated by the same society, and they’ve both been forced to the fringes—Daniele by her past and Grace by her politics. In typical De Palma fashion, this film ends with the audience knowing more than the majority of the characters. We know what happened but, for everyone else, the truth is still hidden in a couch that’s sitting in the middle of nowhere.