The film begins with a slow pan across the cityscape of Manhattan and Central Park, with a minor-key lullaby playing in the background, as superimposed credits flash in a gilded pink typeface. The camera stops when it reaches The Bramford—a giant, well-appointed cooperative apartment building on Manhattan's Upper West Side. Inside the building's courtyard is a real estate agent giving a young couple a tour through the space. When the agent asks what they do, the young man jokes that he is a doctor, and Rosemary assures the agent that her husband Guy is in fact a successful actor. The agent explains to them that The Bramford is a building historically popular with actors, theater professionals, and society types.
They step into a manual elevator, operated by a young African-American attendant, who takes them to the seventh floor. As the real estate agent continues to make conversation with the young couple, we learn they are childless newlyweds, and that the previous tenant of the apartment—one of the first female lawyers in New York City—died in the hospital. Looking around, Rosemary sees a handwritten letter that says "I can no longer associate myself." Rosemary and Guy, her husband, giggle, sneak kisses, and share a joke about marijuana, establishing them as a thoroughly modern pair, seemingly aware of and amused by how they contrast with the stately, old-fashioned character of the building.
The agent is astounded to behold a giant piece of furniture that he calls a secretary blocking the hall closet. Rosemary points out that it has been moved from its original location down the hall. The men marvel at how and why it was moved, especially given that the apartment's previous tenant was 89 years old, and the closet merely contains a vacuum cleaner and some towels. On their walk home, Rosemary pleads with her husband Guy to agree to sign the lease, which he does.
Their friend Hutch helps their lease application with a letter of reference, but warns them about The Bramford. He tells them the building had an "unpleasant reputation" around the turn of the century, including stories and rumors about witchcraft, satanism, and cannibalism. Hutch describes figures like the Trench Sisters, who supposedly cooked and ate children, and a man named Adrian Marcato, who thought he could conjure Satan and was murdered in lobby of The Bramford, which Hutch calls The Black Bramford given its "high incidence of unpleasant happenings." Hutch also tells them a dead infant was found in the basement as recently as 1959.
Later that night, Rosemary and Guy slowly unpack, and Rosemary inspects the hall closet blocked by the secretary and finds some broad shelves. They eat dinner off of one shelf on the floor of the unfurnished apartment, and Rosemary suggests that they have sex. They slowly undress and lie together, until Guy cuts the tension by making a joke about the Trench Sisters.
A visual montage shows the pair decorating and moving their belongings into the apartment. Rosemary pauses to watch Guy's Yamaha advertisement on TV, and shows him the clean, transformed hall closet. Doing her laundry in the basement, Rosemary mistakes another tenant for the Italian actress Victoria Vetri. The tenant introduces herself as Terry Gionoffrio, a struggling actress staying on the seventh floor as a guest of Mr. and Mrs. Castevet. Terry tells Rosemary that the old woman who lived in the apartment before her and Guy was a good friend of the Castevets, often giving them herbs and cooking supplements. The two hear a shattering noise, and after exchanging fears about the gloomy basement, Terry shows Rosemary her "good luck charm"—a beaded silver necklace given to her by Mrs. Castevet with a small orb-like charm attached with "stuff" inside. Rosemary recoils at the smell of it. Terry gushes about how kind and generous the Castevets are, taking her in despite her drug problems, and tells Rosemary her only real family is a brother in the Navy.
In bed, Guy hears the voice of a bickering old woman while Rosemary is washing up, and they realize there is a "partition" between the apartments that allows noise to carry. Guy formally describes the partitions and closets in a mock real estate agent-voice, causing Rosemary to laugh and embrace him. Laying together on the bed, they then hear a soft satanic chorus through the walls that sounds like low chanting mixed with a high-pitched flute.
Walking home one night, Rosemary and Guy see a crowd and police in front of their building. A woman has fallen to her death, lying in a pool of blood on the sidewalk, and Rosemary recognizes her as Theresa Gionoffrio, the woman from the laundry room. A police officer remarks that she stuck a letter to the window with a band-aid before falling to her death. When Mr. and Mrs. Castevet arrive, Mrs. Castevet appears surprised, while Mr. Castevet does not. Mr. Castavet says Terry seemed depressed, but Mrs. Castevet says she seemed happy, and they argue in public about her emotional state and the circumstances leading up to her death. They confirm Terry's handwriting on the suicide note, and when officers ask for next of kin, Rosemary repeats what Terry told her about her brother in the Navy.
Roman Polanski is a director who specializes in generating unease, and he aims to saturate the opening sequence of Rosemary's Baby with foreboding and dread, draped in a superficially lovely exterior. A hushed, sinister lullaby (sung by Mia Farrow herself) intervenes over the Paramount logo, establishing the tone of the psychological horror genre. Against an autumnal cityscape, credits roll in a delicate, bright pink, calligraphic typeface redolent of a formal wedding invitation. These overlapping cinematic elements create an atmosphere of menace and temptation, two aspects central to the Castevets' plot and much of the religious thematic content of the film.
The camera pans across the Manhattan skyline and Central Park, and then lands and zooms out on The Dakota, a real cooperative apartment complex on the corner of 72nd Street and Central Park West, well known since the late nineteenth-century for housing actors and creatives. The exterior shot of The Dakota/The Bramford is one of the key images and symbols of the film, which like Levin's novel, draws richly from the Gothic literary tradition. Within the conventions of this narrative tradition, a curious heroine must navigate a massive castle or edifice, witnessing bizarre happenings along the way, often believed by nobody. Gothic structures function to conceal secrets: architectural secrets like hidden passageways (which Rosemary later finds in the hall closet), and also family secrets (the sordid history of the Marcato coven).
The Bramford is also, crucially, desirable—a highly exclusive, prestigious Manhattan residence, and a potential boon to Guy's career. A quick but meaningful exchange transpires in the first scene of dialogue when Guy says he's a doctor, and Rosemary says, "No, he's an actor!" By the end of the film, everyone in her life will have become a kind of actor, conspiring against her, including Dr. Sapirstein, Dr. Hill, and Dr. Shand. Along with teasing themes of performance and conspiracy, the line suggests the blurry distinction between vocation and persuasion that the conspirators will later exploit—for instance, Guy's acting chops help him manipulate Rosemary, and Dr. Sapirstein's medical credentials helps trump any questions about his reality-defying diagnoses and treatment.
The first major symbol after The Bramford itself is the large secretary blocking the hall closet. Like the Gothic castle, the secretary's function is to enclose, specifically as a storage space, representing the theme of secrecy or concealment. On top of that, the secretary has been moved to block the hall closet, concealing yet another space. This early scene critically foreshadows the film's end, where Rosemary guesses correctly that the hall closet contains a secret passage, which she discovers leads into the Castevets' apartment. In Gothic narrative, architectural features often provide metaphors about family structures; here, the early clue that Rosemary's private apartment might be connected to another space foregrounds the fact that her womb and desire to build a family are from the start vulnerable to an outside, malevolent force. Through a partition in the wall, Guy and Rosemary later hear the chanting of the coven's sabbaths carrying into their bedroom—another architectural symbol of invasion of their private, domestic space.
The second major symbol is the Tannis charm that Rosemary observes around the neck of Terry Gionoffrio. Rosemary first mistakes Terry for the Italian actress "Victoria Vetri," which is the real name of the actress playing Terry Gionoffrio, a model who performed under the stage name Angela Dorian. These self-aware references to actors, acting, and stage names continue to develop the theme of performance introduced in Rosemary and Guy's opening exchange with the real estate agent, and foreshadow Rosemary's epiphany that 'Roman Castevet' is an anagram (or, "stage name") for 'Steven Marcato.' Like the film's opening credits, the Tannis charm simultaneously appeals and unsettles: Terry says its silver charm signifies "good luck," but it emits a noticeably foul odor. Moreover, 'Tannis' is itself a loose anagram of 'Satan.'