The cinematic experience unfolds in the rugged, snow-covered terrain of Iceland, where an unseen force stalks through the frozen landscape, its heavy breathing resonating in the stillness. This mysterious entity eventually finds its way to a rustic barn, where it encounters a flock of sheep, leading to the tragic demise of one innocent creature.
In the heart of this icy wilderness, we find Maria (Noomi Rapace) and her husband Ingvar (Hilmir Snær Guðnason), a quiet couple deeply entrenched in their rural lifestyle. Their days are spent devoted to their sheep and the regular rhythms of farm life, marked by Ingvar’s solitary excursions across the sweeping landscape, often accompanied by their beloved dog.
As Christmas Eve draws near, their tranquil routine is abruptly interrupted upon the discovery of a lamb born with an unusual deformity within their flock. Overwhelmed with compassion, they decide to care for the little creature, naming her Ada. This newfound responsibility injects fresh purpose into their lives; particularly for Ingvar, whose emotions are stirred in reflection of the beauty of existence.
However, Maria’s maternal instincts soon lead her to become excessively protective of Ada. Her vivid dreams—filled with rams and sheep glowing with an otherworldly, sinister light—foreshadow a growing unrest that contrasts with her calm exterior.
Meanwhile, in a remote area, a group of strangers violently dispose of Pétur (Björn Hlynur Haraldsson), a man whose destiny is intertwined with the mysterious events in Maria's life. As Pétur fights to regain his footing, he unwittingly heads towards the home of the couple, oblivious to the foreboding darkness that lies ahead.
The peace of Maria and Ingvar's life is shattered when they realize that Ada is missing one afternoon. In a frantic search, Maria heads to the barn and confronts Ada's mother. Driven by instinct, she makes a heartbreaking decision—ending the sheep's life and burying her far from sight. This pivotal moment is witnessed by Pétur, whose presence signals imminent chaos for the couple.
Upon entering their humble home, the air is thick with secrets as Pétur is revealed to be Ingvar's brother. The connection seems intimate, hinting at a deeper bond shared between Pétur and Maria. As they gather for a meal, Ada’s peculiar presence is revealed—she walks on two legs, and her left arm bears strikingly human traits. An unsettling dynamic emerges as Pétur observes Maria bathing with Ada, noticing disturbing similarities between Ada's form and that of a human.
Curious yet apprehensive, Pétur questions Ingvar about their unusual family dynamic. Ingvar reassures him of their happiness, yet Maria’s discomfort is palpable, aware of Pétur's volatility. As Pétur becomes entwined in their family life, his initial horror towards Ada—viewing her as a mere animal—persists.
As the night progresses, Pétur's inner conflict heightens, leading to a secretive attempt to eliminate Ada while Ingvar and Maria sleep. However, he is unable to go through with it, and the next morning reveals an unexpected sight: Ada nestled peacefully in Pétur’s arms, alongside her brother.
In a sorrowful moment, Maria leads Ada to the grave of their stillborn child, the very namesake for Ada. As the family dynamics shift, Pétur grows fond of Ada, treating her as a surrogate niece while Ingvar and Maria nurture their troubled relationship. Despite the festivities of the night, a sinister presence looms outside as the unseen creature from earlier returns, mercilessly claiming their dog before seizing their weapon.
As Ingvar succumbs to drunken slumber, Pétur, frustrated and restless, makes advances towards Maria, who firmly rejects him. The air thickens with tension when he alludes to witnessing her take Ada's mother’s life, hinting at secrets that threaten their fragile peace.
In a moment of calculated defiance, Maria kisses Pétur and then confines him to a closet for the night, allowing the echoes of his protests to linger in the atmosphere as her haunting melody fills the air—signaling the brewing storm within.
With dawn breaking over the landscape, Maria sends Pétur off to the bus stop, a mix of sorrow and relief painted across her face. She passes him a small fortune as a gesture for a new beginning. Meanwhile, Ingvar leads Ada through the fields, their laughter echoing under the bright sky.
However, Maria’s calm is shattered when she hears a distant gunshot upon returning home. Rushing to the source, her heart plummets as she discovers Ingvar, fatally wounded by a grotesque ram, possibly connected to Ada's origins. The creature, having claimed Ingvar, reaches for Ada, who finds herself torn between fear and a longing for her father.
In a moment of despair, Maria flees and searches for Ingvar, finding him on the brink of death. Despite her desperate pleas for him to reveal Ada's location, he passes away, leaving Maria consumed by heartbreak and confusion. Standing amid the remnants of her shattered world, she laments the loss of both her friend and the child, enveloped in profound sorrow as she confronts the grim reality of her fate.
