U.S. Marshal Carrie Stetko is stationed at a remote research base in Antarctica, tasked with maintaining order in one of the harshest environments on earth. Just as she prepares to leave her post and return to civilian life, the body of a geologist is found in the ice, marking the first-ever murder in the frozen continent. With only three days before the sun sets for six months, plunging Antarctica into winter darkness, Carrie reluctantly begins her investigation, racing against time and worsening weather conditions. She is joined by UN operative Robert Pryce, who arrives from another base to assist with the case. Together, they delve into the dead man's activities, uncovering clues that point toward something far more sinister than an isolated homicide.

As the investigation progresses, Carrie uncovers secrets that hint at a high-stakes conspiracy involving stolen artifacts from a Russian cargo plane crash decades earlier. With each lead, the dangers intensify, and Carrie finds herself targeted by an unknown assailant who will stop at nothing to protect the hidden truth. Facing brutal weather, the psychological toll of isolation, and a rapidly closing window of daylight, Carrie must navigate the treacherous environment and unravel a mystery entwined with greed and betrayal. The pursuit for answers becomes a fight for survival, pushing her to the limits as she confronts both external threats and internal demons.