The fourth season of Night Country commences in Alaska, specifically on December 17th, the final sunset of the year. The scene opens with a man aiming his rifle at a herd of cattle. As they charge towards him, they leap off what appears to be a precipice, a breathtaking cliff edge.
Meanwhile, at the Tsalal Arctic Research station nestled in the heart of Ennis, Alaska, a group of men are engrossed in watching Ferris Bueller's Day Off on the television in the cozy rec room. Suddenly, bizarre occurrences start to unfold, and one of the men shouts out, 'She's Awake.'
Cutting to December 20th, a delivery man approaches the isolated research station. He carries the package inside, but finds no one present to sign for it. As he surveys the eerily quiet surroundings, his gaze falls upon a severed tongue lying on the floor, while the men remain mysteriously absent.
Chief of Police Liz Danvers arrives on the scene to investigate the baffling disappearance of the men, accompanied by fellow officers Hank and Peter - a father-son duo. Ferris Bueller's Day Off continues to play on the television, seemingly unstoppable. Danvers rummages through the station, eventually locating the stop button on the DVD player and shutting off the persistent film.
During her investigation, she discovers that the research station has been dedicated to exploring arctic geology for 18 years. In the main area, she notices something strange scribbled on the whiteboard, piquing her curiosity.
Danvers suspects that the incident might be linked to a cold case involving the brutal murder of a woman named Annie Kowtok. She also believes that the severed tongue could belong to a member of the indigenous tribe. A younger agent named Evangeline Navarro approaches her with questions, as she had originally been assigned to the Kowtok case before being demoted to trooper status due to her obsessive pursuit of it. However, Danvers remains tight-lipped about the details, infuriating Navarro to the point of storming out of the police station.
The gruesome details of Annie Kowtok's murder are revealed - she was stabbed 32 times with a star-shaped weapon, and her tongue was brutally severed. This grisly connection leads Navarro to believe that the men's disappearance could be intimately tied to Kowtok's unsolved murder.
Later, Danvers' personal life takes a tumultuous turn as she rushes to pick up her daughter from a friend's house. It turns out that her daughter has been caught making a sex tape, and the friend's mother is furious, screaming angrily at Danvers. Amidst this drama, they become involved in a minor car accident caused by a drunken woman who swerves dangerously in front of them. Danvers quickly arrests the intoxicated woman, and soon, the police arrive to take her into custody.
Navarro made her way to Annie's brother to check on his well-being and remind him that she hadn't forgotten their case. However, her thoughts were interrupted by a frantic call from a colleague, urging her to rush to her sister Jules' house. Jules had suffered another anxiety attack, and Navarro's heart went out to her as she heard the panic in her voice. Jules confessed to Navarro that she dreaded ending up like their mother, a fate Navarro was determined to prevent.
Liz, meanwhile, appealed to Hank to locate the Annie Kowtok case files. The flood had forced him to store them at his house, and Liz needed them urgently. However, Hank's casual attitude towards the matter frustrated her. She turned to Peter, asking him to retrieve the files from Hank's house. Reluctant but dutiful, Peter agreed, and Liz pored over the case, revealing fresh insights to Peter after he confessed the risks he had taken to secure the files.
Elsewhere, Navarro visited a casual lover, engaging in a passionate encounter before stealing his toothbrush. As she left his abode, she mischievously poured Bailey's Irish cream into the petrol cap of a cocky white man's car. Navarro's investigation took a turn when she pursued a lead regarding Annie's potential knowledge of the Tsalal station. Suddenly, her progress was halted by an unexpected encounter with a hulking white polar bear blocking her path.
Danvers, meanwhile, delved deeper into the case, laying out the files of the missing men. As she reached for Annie's case files, her attention was drawn to a picture where a scientist was wearing Annie's torn parka jacket. This discovery sparked a new line of inquiry, and Danvers headed back to the Tsalal lab to search for the elusive parka. Her investigation collided with Navarro's as they both hunted for clues connecting the dots.
Despite not finding concrete evidence at the lab, they both suspected that the scientists had something to do with Annie's demise. The episode reached a climax when Danvers received a call from Peter, informing her that a woman named Rose had stumbled upon something significant on the ice. Rose claimed that her deceased son Travis had led her to the crime scene, where she had discovered the frozen corpses of the scientists.
Danvers and the other police officers raced to the scene, their hearts heavy with the knowledge that they were finally closing in on the truth. As they arrived, they were confronted with a chilling sight: the dead bodies of the scientists, half-buried in the ice, their secrets frozen in time.
