After undergoing cosmetic facial surgery, a mother, portrayed by Susanne Wuest, returns to her sleek, isolated lakeside home, where she is greeted by her ten-year-old twins, Elias and Lukas, played by Elias and Lukas Schwarz. With her head wrapped in bandages, revealing only her eyes and mouth, her altered appearance deeply unsettles the boys. As her peculiar behavior becomes more pronounced, the twins find themselves increasingly disturbed. The mother neglects Lukas entirely while seemingly favoring Elias in their conversations.
Strangely, she compels them to keep the blinds drawn during the summer sun and imposes a strict silence inside the house, permitting only outdoor play. Her sudden cruelty shocks the boys as she harshly punishes Elias for minor mischief—behavior they find hard to reconcile with their once-loving mother.
As suspicion grows, the twins uncover an old photograph portraying their mother alongside an unfamiliar woman dressed in similar attire and possessing similar features. Their fear that the woman inhabiting their home might be an impostor escalates, prompting them to bind her to the bed and demand the whereabouts of their true mother. Despite her claims of being their real mom, the twins resort to sealing her mouth with tape to prevent her calls for help.
Simultaneously, two Red Cross workers arrive to collect donations, initially waiting for the mother’s return. However, they leave after Elias discreetly hands over a significant sum of money, which he pilfered from his mother's purse. In a desperate attempt, the woman manages to break free from the tape and screams for assistance, but it's too late to catch the workers' attention. The twins then use Super Glue to seal her lips, realizing soon after that this prevents her from eating, forcing them to use scissors to cut her lips open.
As the woman remains bound, an unfortunate accident occurs, leading to her momentary release. Seizing the opportunity, she seeks to overpower the twins to escape, but they have set a trap that causes her to fall and lose consciousness. When she regains her senses, she finds herself glued to the living room floor. In a drastic move to extract the truth about their mother, Elias resorts to burning the house down, pressing the woman to confess.
The plot takes a tragic turn as the mother reveals that Lukas died in an accident prior, a heartbreaking truth that she conveys to Elias. Tearfully, she reassures him that he was not to blame for Lukas's death and implores him to release her, emphasizing their need to move past the tragedy. To prove her identity, Elias challenges her to tell them about Lukas's current condition. However, as she is unable to perceive the imagined Lukas, Elias becomes convinced that she isn't their mother. In a fit of anger, he ignites a curtain, leading to a devastating outcome where the mother is engulfed in flames and succumbs before the firefighters arrive.
The film concludes with a poignant, ghostly scene of the mother reunited with her twin sons amidst the serene backdrop of a cornfield, signifying their eternal bond.
