Anne is a dedicated lawyer residing in Denmark alongside her husband, Peter, and their delightful twin daughters, Frida and Fanny. The family dynamic, however, becomes complicated with the impending arrival of Gustav, who is Peter's teenage son from a previous marriage to Rebecca and currently lives in Sweden. As plans are laid for Gustav to move in with Anne and Peter, this transition sets the stage for a tumultuous journey that alternates between familial bonding and deep-seated conflict.
When Gustav arrives, Anne attempts to cultivate a relationship with him, but the tension quickly escalates, particularly between Gustav and Peter. Struggling against being treated like a minor, Gustav insists on his right to live independently, despite his lack of maturity. One fateful day, Anne discovers that their home has been the target of a burglary. In the aftermath of this alarming event, Anne reports the crime to the police, but soon uncovers something shocking hidden in Gustav's laundry—an item that she recognizes as belonging to her bag stolen during the incident. This revelation leads Anne to confront Gustav with the undeniable evidence of his guilt.
In a twist of moral compromise, Anne resolves to keep this secret if Gustav agrees to fulfill certain responsibilities around the house. Thus begins a strained yet seemingly harmonious coexistence. Gustav, now fully integrated into the family, charms the twins by reading aloud the Danish version of Alice's Adventures in Wonderland, a beloved activity that Anne herself enjoys. As days blend into weeks, the tension of their unconventional living arrangement begins to bloom into something more complex when Gustav introduces his girlfriend, Amanda, to the family. However, Anne is less than thrilled by the intimate sounds she hears coming from Gustav's room.
In a shocking turn of events, as Anne and Peter host friends on their balcony, Anne finds herself drawn to Gustav. What begins as an innocent flirtation ignites into a secret romance when she kisses him at a bar, eventually leading to a passionate encounter in his bedroom later that night. Their relationship unfolds in shadows; they record playful interviews where Gustav asks Anne about her past, including her first sexual encounter—an experience she admits was with someone unsuitable, though she refrains from disclosing any names.
The turning point arrives when the family celebrates the twins’ birthday. In a moment fraught with tension, Gustav kisses Anne, who instinctively protests, urging him to stop. This incident does not go unnoticed; her sister, Lina, witnesses the kiss and in distress departs from the celebration. Following this, Gustav and Peter retreat to their cabin in the woods, and upon their return, Peter reveals that Gustav has expressed a desire to enroll in a boarding school—along with unsettling news of an affair involving Anne.
Anne vehemently denies any wrongdoing, insisting that Gustav harbors animosity towards her due to her role in the dissolution of Peter and Rebecca's marriage. However, the weight of the truth hangs heavily between them when confronted with the aftermath of Gustav's actions, including the burglary. As tensions mount, Gustav ultimately leaves for boarding school, creating an emotional divide.
The narrative spirals as Gustav visits Anne at her office, angrily threatening her if she does not confess to Peter about their liaison. She retorts, asserting that no one would believe such an accusation. Later, his desperation leads him to her home, demanding to see his father. As Anne pushes him away, ignoring his pleadings, he succumbs to tears on the floor, leaving behind a shattered trace of their once-potential bond.
The story takes a tragic turn when Peter receives news that Gustav has gone missing from school, prompting a police investigation that tragically concludes with the discovery of Gustav's frozen body near the cabin. Overwhelmed with guilt, Anne breaks down in the bathroom, haunted by the thought that she is to blame. The weight of despair becomes palpable when she conjures the illusion of Gustav, a vision that forces her to confront her grief. However, the confrontation is abruptly interrupted by Peter’s anger, who vehemently dismisses her attempts to absolve him from blame. In this heart-wrenching conclusion, the family is left to grapple with an unbearable loss as they prepare for Gustav's funeral, forever marked by the events that transpired.
