Norway, winter. Introverted and hard-working Nils drives the powerful snow plough that keeps open the roads and mountain passes of the inhospitable frozen landscape where he lives. He’s just been named citizen of the year for his efforts when he receives news that his son has died of a heroin overdose. Refusing to believe the official version of his son’s death, he begins a covert search for the boy's alleged murderers. A surprising turn of events causes him to become a tough-as-nails and feared underworld hero – one whose identity nobody knows.