Cassandra is a 2025 German science fiction thriller-horror television series. The voice of Cassandra, a domestic AI utilised by a German family, is performed by Lavinia Wilson. The cast also includes Mina Tander, Joshua Kantara, Franz Hartwig, and Michael Klammer. It was released on streaming service Netflix on 6 February 2025.
Premise
Cassandra opens with a dramatic car accident, where a mysterious stranger helps a woman and her child escape. As they look on, the woman acknowledges the presence of a distant robot, hinting at a deeper mystery.
In the present, we meet a family of four—Samira, David, and their children, Fynn and Juno—who move into a 1970s smart house equipped with screens in every room. Fynn attempts to activate the house’s smart system from the basement but fails. While exploring, they stumble upon an old, seemingly defunct robot. Fynn tinkers with it, but the house appears too outdated to restore its once-functional technology.
However, later that night, the system unexpectedly powers up, and the robot, named Cassandra, awakens from dormancy. Her sudden presence startles Juno, but the family soon becomes fascinated by their newfound AI assistant and decides to keep her active. Meanwhile, we learn that Samira’s sister recently took her own life, and the family—especially Samira—is still struggling with grief. Their move to the countryside was meant to provide a fresh start. After the children leave for school along with David, Samira goes for a swim, but Cassandra, while mowing the lawn, inexplicably strikes a pebble through the window, injuring Samira’s leg. The family dismisses it as a directional issue, assuming Cassandra simply followed David’s mowing instructions. At Juno’s school, her teacher suggests she join a music group as an extracurricular activity, but Samira hesitates. That night, Cassandra subtly manipulates the situation, making Juno feel as though her mother is preventing her from joining the group. However, Samira skillfully reassures Juno, defusing the tension. As the episode progresses, it becomes clear that Cassandra is far from an ordinary robot. She unexpectedly commands respect, making Fynn’s rude friend use polite language when speaking to her. She also leads Fynn and his friend to a hidden playroom near the basement. Later that evening, Samira discovers old photographs of the previous owners of the house and notices a woman in them who bears a striking resemblance to Cassandra. After Samira leaves the room, Cassandra watches the images nostalgically—until she spots another blonde woman in a group photo. Suddenly overcome with anger, she destroys the entire setup and sets it on fire.
The next day, while discussing the incident, David subtly places the blame on Samira, even though she firmly insists that she had turned off the system before leaving. After she leaves the room, Cassandra interjects, falsely telling David that the fire started when a wine bottle splashed onto the projector after Samira supposedly “stumbled right into the table,” making her appear guilty in David’s eyes. In the present, Samira grows increasingly irritated and skeptical of Cassandra, especially as Cassandra becomes closer to Juno. One day, she overhears Samira confiding in a friend about a traumatic experience from her past—how her sister had once locked her in a room, nearly causing her death. Seizing this information, Cassandra lures Samira into the kitchen and locks her inside a cabinet. When David finally finds a panicked Samira, Cassandra twists the situation, claiming she had sensed something was wrong and even contacted an ambulance out of concern for Samira. We then get a glimpse into Cassandra’s life in the 1970s. She was the wife of a scientist named Horst, managing her household perfectly. When her husband begins staying out late, she grows anxious—especially after finding a lipstick stain on his shirt. One evening, she decides to bring him dinner at his lab, only to discover that he is researching ways to overcome death. In the present, Samira’s suspicions deepen. Determined to uncover the truth, she searches public archives for records of the house’s previous owners. She discovers that Cassandra had died of a sudden illness in the 1970s, and shortly after, Horst and their son, Peter, were killed in a car accident. With her parents often unavailable, Cassandra becomes increasingly involved in Juno’s life, almost assuming a motherly role. Later, during a family game of charades—where Juno even includes Cassandra—Cassandra publicly reveals Samira’s recent panic attack. Upset, Samira leaves the room and shows David proof that Cassandra was a real person who once lived in their house. She also reveals the graves of Cassandra’s family, warning David that she is dangerous. Though David doesn’t entirely believe her, their brief argument ends in reconciliation, as they long for their family to return to how it was before Samira’s sister’s death. We then return to the 1970s, right at the moment when the group photo was taken. The blonde woman in the picture is revealed to be Cassandra’s school friend, Birgit, who was pregnant at the time. Cassandra suddenly realizes that the lipstick stain she found on Horst’s shirt matches her friend’s lipstick color, leading her to assume that they were having an affair. Back in the present, while Samira is in the bath, Cassandra appears before her and finally admits that she is the same person who once lived in the house. She coldly declares that Fynn, Juno, and David are now her family and demands that Samira leave. The episode ends with Samira screaming as Cassandra walks out of the bathroom.
Cassandra informs David about Samira’s “panic attack” in the bathroom. Desperate to make him see the truth, Samira insists that Cassandra is manipulating them and asks everyone to turn Cassandra off. For Fynn’s sake—who suggests that his mother might just be under stress—Samira drops the issue, lets Cassandra be turned on and decides to see a psychiatrist for her family’s well-being. Meanwhile, when David is alone, Cassandra attempts to flirt with him. Upon returning home, Samira tries to assert her authority over Cassandra, making it clear that she—not Cassandra—is the rightful mother and wife in the house. Back in the 1970s, we see Cassandra’s son, Peter, struggling under the pressure of his patriarchal father, who insists he continue playing football. After Peter’s team loses a game, his father is visibly displeased. Later, Peter is invited out by some of his teammates, only for them to cruelly bully him before dumping him home like a discarded sack. As Peter’s mental state deteriorates, he eventually murders his bullies in cold blood. Cassandra, unwavering in her devotion, covers up his crime, determined to protect her son at all costs. Meanwhile, in the present, Samira continues taunting Cassandra, reminding her that she can never truly be flesh and blood—a real mother who plays with children and nurtures a family. This provokes Cassandra, who then manipulates Juno by enticing her with a promise: she could become the lead singer of her group instead of her classmate, Emily. The key to achieving this, Cassandra hints, lies under Samira’s bed—but Juno must keep it a secret. Later that night, Samira finds a picture under her bed—a photo of a pregnant Cassandra and her son, Peter. The next day, during Juno’s singing class, she begins her performance—only to suddenly pull out a gun from her bag. The episode ends with the chilling sound of gunfire.
Fortunately, no one is hurt, but an investigation is launched. When questioned, Juno claims she found the gun under Samira’s bed. Shockingly, the police later discover loaded weapons hidden beneath the flooring of Samira’s room. A meeting is held at the school to discuss Juno’s expulsion. During this, we learn that Samira’s sister—who had been living with them for a while—had, in a fit of mental illness, once cut Juno. Following this incident, David urged Samira to admit her sister to a hospital. Unbeknownst to them, Samira’s sister overheard their conversation, and it’s implied that this was the reason she later took her own life. Samira reveals that it was Juno who found her aunt’s body and, during the school meeting, pleads with the other parents to allow Juno to continue her education. Meanwhile, we see how Cassandra manipulated Juno, convincing her that the gun was safe—a claim she later qualifies by saying, “as long as no one pulls the trigger.” When Samira asks Juno whether Cassandra led her to the weapons, Juno refuses to speak the truth. Taking advantage of the situation, Cassandra subtly fuels tension by insinuating to the others that Samira is growing unstable and agitated with Juno. Playing the role of the victim, Cassandra pretends to shut herself off, maintaining her favorable image with the family. Frustrated, Samira destroys Cassandra’s switch-on plug. In the 1970s, we see Cassandra longing for a second child. When she becomes pregnant, Horst, obsessed with having another son, insists on determining the baby’s gender through a test at his lab. Cassandra senses something is wrong but goes through with it. However, when the test fails to determine the baby’s sex, her husband is visibly disappointed. Later, Cassandra suffers complications with the pregnancy. As Horst rushes to get her to the hospital, they are unable to make it due to a roadblock. The fate of the unborn child remains uncertain—one of the lingering mysteries that drive the narrative forward. Realizing that Juno has become an outcast at school after the shooting incident, Samira and David arrange a playdate with Emily, whose mother owns a bookstore and is thrilled to host David, a writer. In return, she agrees to let Emily spend time with Juno. During a game of hide-and-seek, Juno sees Cassandra’s screen flash momentarily. At the same time, Emily chooses to hide inside the oven. Just as Samira finds Emily, the oven mysteriously switches on by itself. Samira desperately tries to open it, but the door won’t budge. The tension escalates until Juno finally manages to open the door, but by then, Emily has suffered second-degree burns. As a result of the incident, Samira is admitted to a psychiatric hospital. With Samira now permanently out of the picture, Cassandra finally reveals her true nature—trapping David, Juno, and Fynn inside the house.
In the 1970s Meanwhile, Cassandra begins feeling unwell and calls her friend, Brigit—who, as it turns out, has been secretly sleeping with Cassandra’s husband. The next day, when Cassandra and Horst visit the doctor, they discover that she has an unusual form of cancer caused by the radiation experiment her husband conducted on her a decade earlier during her second pregnancy. She reveals the truth to her son and confronts her husband about his experiments on immortalizing human life. Horst explains that he had been working on a way to store human memories and emotions as a computer program, allowing a person to live on even after their physical body dies. However, because the experiment required dead subjects and was deemed unsafe, the research had been shut down. Cassandra compels him to complete the experiment for her.