In 1859, a meteorite blazes through the sky and crashes into the Gela Alta glacier in western Greenland, triggering a cataclysmic explosion that tragically ends the life of an Inuit fisherman.
Fast forward to present-day Copenhagen, where Smilla Jaspersen, a Greenlander studying ice crystals at a university lab, finds herself in a precarious situation. Despite her expertise as an Arctic ice specialist, she is still navigating the waters of unemployment, burdened by a troubled past. Upon returning to her apartment complex one evening, Smilla discovers the lifeless body of Isaiah Christiansen, a six-year-old boy from her neighborhood, lying in the snow at the edge of the building. Though the police deem his death as an accident caused by a fall from the roof while playing, Smilla's instincts tell her otherwise, especially since Isaiah had a fear of heights. A look at the roof reveals that his footprints lead directly to the edge, suggesting something more sinister.
At the morgue, Smilla encounters Dr. Lagermann, who shocks her by revealing that a well-known professor, Dr. Johannes Loyen, conducted the boy's autopsy. When she consults with Loyen the following day, he dismissively labels Isaiah's death as a mere accident. Unwilling to accept this, Smilla files a complaint with the District Attorney. Her search for answers leads her to Lagermann's home, where he discloses a critical detail: he found a puncture wound on Isaiah's thigh, made by a biopsy needle post-mortem. Lagermann also shares that Loyen had been examining the boy monthly.
During the funeral, Smilla witnesses Dr. Andreas Tork, CEO of Greenland Mining, attempting to bribe Isaiah's mother, who refuses his offer in anger. After her husband's untimely death in Greenland linked to mining issues, she had been offered a pension by the company. Detective Ravn from the District Attorney's office agrees to investigate, but Smilla soon discovers he has connections with Tork. Determined, Smilla tracks down the former accountant of the company and manages to access a report detailing their dubious activities in Greenland. A neighbor mechanic steps in to help her with the investigation.
However, when Detective Ravn threatens Smilla with imprisonment for stealing property belonging to Greenland Mining, she finds herself at a crossroads. She reluctantly agrees to halt her inquiry but continues after learning from Isaiah's mother that her late husband died due to something related to the mine's contaminated meltwater. Seeking further assistance, Smilla enlists her father, Moritz Jaspersen, to help her decode the Expedition Report.
While searching around Isaiah's old hiding spot in their apartment complex, Smilla discovers a hidden cassette tape within the wall. Unable to decipher it alone, she consults a blind audio expert, Licht. Shortly after revealing that the tape includes a conversation between Isaiah and his father, Licht is tragically murdered, forcing Smilla to flee. With help from the mechanic, they follow suspicious individuals aboard a ship Tork is using for another mining expedition.
Smilla's father provides her with medical x-rays from the report, unveiling a startling truth: a predatory and prehistoric "Arctic worm," believed to be extinct, is responsible for the mine workers' "accidental" deaths. As the worm invades the body, it wreaks havoc on organs, leading to toxic shock and death.
Desperate to expose the truth, Smilla infiltrates the mining ship by posing as an employee, where she meets Nils Jakkelsen. Together, they uncover videotapes that reveal the mining company's knowledge of an energy-generating meteorite they uncovered alongside the parasitic worm. Tork envisions the meteorite and its potential to elevate his company to unprecedented heights in the industry. They also find a recording of Professor Loyen conducting a medical examination on Isaiah. The tension escalates as Smilla must evade Tork's henchmen, who ultimately kill Nils in the chaos.
As the ship approaches the shore, Smilla bravely departs, navigating the treacherous, frozen terrain. She locates the entrance to the ice cave where Greenland Mining is conducting research on the meteorite. Inside, she discovers Tork, who reveals that Isaiah's father was infected by the parasitic worm during a dive near the meteorite. Loyen had been monitoring Isaiah for signs of infection. Tensions rise to a boiling point, leading to an armed confrontation. In a tragic twist, Professor Loyen falls into the icy pool harboring the meteorite, instantly freezing to death.
In a desperate attempt to flee, Tork escapes across the ice, but Smilla is hot on his heels. She recounts the harrowing events leading up to Isaiah’s death, detailing how Tork had stalked the boy home, leading to the rooftop incident. Meanwhile, the mechanic detonates a powerful bomb, collapsing the cave and entombing anyone left inside.
The ensuing waves force Tork into the freezing waters, drowning him as Smilla stands atop the ice, surveying the snowy landscape that once echoed with the innocence of her childhood. Amidst the desolation, she wrestles with her emotions and the specter of injustice that looms large, reflecting on the harsh realities of both nature and humanity.
