Sacrifice

Ben and Max arrive at a suburban Berlin house where a group has committed mass suicide. The police reveal the victims took cyanide in shifts, each body found with a seashell in the mouth and a black smear on the cheek. Nina, a forensic detective, explains the unusual evidence before Ben texts Mazzy to stay safe and come later.

While Mazzy navigates the trip to Berlin, a young man helps her and introduces himself as Martin. He offers directions and they exchange phone numbers, foreshadowing his influence over her perception of the group. The connection hints at how the cult's network begins to touch Mazzy's life.

Back in Berlin, Ben deepens his work on how cults operate, including interviews with a member who will only speak behind Mazzy's door. He collaborates with Max and Nina as the investigation expands, pulling him further into the group's orbit. The research intertwines with Mazzy's growing exposure to Hilma's circle.

Mazzy and Martin spend time together, sharing coffee and visiting the woods where they experiment with shrooms. The companionship masks a manipulative layer of the group’s dynamics as Mazzy becomes more entwined in Martin's world. Her curiosity about her father's project grows through these interactions.

One evening, Mazzy, Ben, and Nina join Max for dinner with his wife and Elsa. Mazzy probes Elsa about Nina, and Elsa says Nina is only a colleague. The family-style gathering blurs personal and professional lines and deepens Mazzy's suspicion of the group.

Flashbacks reveal Martin's closeness to his grandmother and his involvement with Hilma's environmental activist group. He starts bringing Lotte to meetings, while the grandmother's death leaves him emotionally fragile. The history helps explain Martin’s role in Mazzy's fate.

A girl drowns in a lake with stones in her pockets, but without a shell or a marked cheek. Nina and her team respond, but determine the death is not linked to the mass suicide. The incident widens the circle and adds a new layer of worry.

Mazzy begins listening to Hilma's lectures and attends a protest with Hilma and members of the group. Hilma is welcoming and even gives Mazzy the necklace she wears, deepening Mazzy's sense of belonging. Ben and Nina grow closer professionally as the group tightens its grip.

Nina asks Ben to meet for a drink, and he leaves Mazzy a note saying he will be at a bar. Mazzy wakes to find him kissing Nina, which upends her belief in his claimed single status and fuels her distrust. The conflict strains the fragile trust between father and daughter.

Mazzy goes to an underground club with Larissa; Martin is there and notices a man pressuring Mazzy to dance. Martin intervenes by stabbing the man with a broken bottle, and Mazzy and Larissa end up sleeping in a park due to their intoxication. The night cements Martin's dark side in Mazzy's mind.

At dawn, Martin brings Mazzy to the group's center. She is pulled into an initiation ritual, begs to call her father, and is knocked out with chloroform. Hilma orders Martin to take Mazzy to the lake, tightening the group’s plan to remove her.

During the confrontation, Hilma reveals lines from Lotte that expose her identity and connect Mazzy to the circle. Ben realizes Nina and Hilma control the group and that Mazzy has likely been taken toward the lake. The seashell necklace seals the link to the mass suicides.

Nina, Hilma, and the others don ceremonial robes, place shells in their mouths, smear ash on their faces, and douse themselves with gasoline before lighting themselves on fire. Hilma exits as the ritual unfolds, leaving the others to enact the final act of the group's indoctrination. The center burns while Mazzy's fate hangs in the balance.

Mazzy wakes from the drug-induced state and wanders toward the lake, hallucinatings. Ben arrives with the police and dives into the water to pull Mazzy to safety as Martin and the others die around the shore. The moment ends the immediate threat but marks the collapse of the cult.

Ben and Mazzy embrace in tears after Mazzy's rescue, while Martin and most of the cult perish and Hilma survives. Elsa later discovers a Hilma video online, staring entranced as Mazzy did, suggesting the group's ideas continue to haunt others. The film closes on a note of unsettling aftermath.