Behind the scenes of her quiet routine, fifty-year-old Halla leads a double life as a passionate environmental activist. Known to others only by her alias “The Woman of the Mountain,” Halla secretly wages a one-woman war on the local aluminum industry. As Halla’s actions go from petty vandalism to outright industrial sabotage, she succeeds in pausing negotiations between the Icelandic government and the corporation building a new aluminum smelter. But right as she begins planning her biggest operation yet, she receives an unexpected letter that changes everything: her application to adopt a child has finally been accepted and there is a little girl waiting for her in Ukraine. As Halla prepares to abandon her role as saboteur and savior of the Highlands to fulfill her dream of becoming a mother, she decides to plot one final attack to deal the aluminum industry a crippling blow.