At the Tsalal Arctic Research Station the men who operate the station go about their usual routine; putting on a load of washing, cooking a meal and watching TV. Suddenly one of the men begins shaking before turning to his colleague with a shocked look on his face and exclaiming “She’s awake”.

Cut to the third day of night in the Arctic a van arrives at the research station with some food supplies. Entering the building the delivery driver discovers that the men have vanished without a trace before finding a human tongue on the kitchen floor.

Detective Liz Danvers (Jodie Foster) arrives at the Arctic Research Station where Hank and Peter - fellow police officers who are also father-and-son - give her the rundown on the case revealing that the scientists were last in contact with the town a week prior when they called in for some supplies. As Liz looks around the station she finds evidence suggesting that the men disappeared at least 48 hours ago.

Across town and out on the ice, a woman – later identified as Rose - guts a wolf before she spots a man, whom she calls Travis, in the distance.

Back at the police station, local trooper Evangeline Navarro (Kali Reis) is waiting in Liz’s office having heard about the tongue and wanting to know if it links to an unsolved case from years ago. The pair have clear history but Liz is soon called away to collect her stepdaughter. Whilst arguing in the car with her stepdaughter, Liz narrowly avoids a car accident and finds the driver of the other car drunk and arrests her.

That evening Liz calls Peter to get him to go round to his father’s house to steal an old case file that he has in his home. Dropping the case file to Liz’s home, she updates him on the cold case that Evangeline was asking about revealing that the victim, Annie, was found with a missing tongue proving a possible connection between the two cases.

Later that night, as Liz looks through case images from the research station, she opens the files from the unsolved case of Annie K and spots a connection – one of the workers from the station was wearing a similar coat to one from Annie’s case. Heading to the research station to investigate further, Liz finds Evangeline there and tells her about the possible connection she’s found between Annie’s case and the current case. The pair beginning looking around the station trying to find the coat seen in the photo before Liz gets a call telling her that Rose has found something out on the ice…frozen bodies.

Out on the ice Liz and the police team examine and photograph the crime scene, taking note of how the victims are all naked – some with their eyes scratched or burnt out.

Liz heads to the local school to find out from the geology teacher exactly what they were researching at Tsalal. He reveals they have spent decades trying to sequence the DNA of an extinct microorganism that has the potential to cure cancer and genetic disorders.

Rose is able to communicate with the dead and tells Evangeline about what Travis has told her in the years he’s been visiting her since he passed away. Evangeline asks questions in an attempt to understand more about what her sister who suffers from mental health problems is going through. Before Evangeline leaves, Rose mentions the spiral mark that was on the forehead of one of the bodies revealing that it’s “older than Ennis”.

Liz returns to the station where she finds her superior officer, Capitan Connelly, waiting for her. He’s travelled down determined to take over the case and move the investigation up to Anchorage. But Liz quotes regulation about the handling of frozen bodies which buys her 48 hours whilst they thaw to an appropriate temperature.

Needing a place to thaw the bodies, Liz heads to the ice hockey rink to speak with the owner Kate. The pair clearly share a history but Kate reluctantly agrees to them using the rink, making it clear that she’s not doing it as a favour for Liz but for the good of the town.

With the frozen corpses now at the ice rink, Liz and Peter examine them noting a number of self-inflicted injuries. Evangeline shows Liz an image of a spiral tattoo Annie had on her body – the same design that is on the forehead of one of the bodies.

Liz and Peter run through theories to try and figure out why the men were out on the ice undressed, with their clothes folded neatly on the side. Peter unlocks the phone of one of the researchers and finds the video which shows his co-worker trembling and saying “She’s awake” – filmed on the day they went missing.

Wanting to find out more about the researchers at the station, Liz goes to speak with the cleaning lady who worked there and Peter speaks with the delivery driver, Wallis. They both attest to one of the men, Clark, acting strangely and Wallis reveals that he thought he saw someone at the station the day he discovered the men had vanished. When shown a picture of the spiral shape, he reveals that Clark had it tattooed on his body.

Liz sends Peter to watch over the frozen bodies overnight, leaving his wife frustrated. Liz heads to Peter’s house to pick up her stepdaughter Leah and is angry to find her exploring her heritage by applying a temporary facial tattoo. That evening at the ice rink, Hank confronts Peter about stealing from him telling him to remember that “blood is blood”.

Liz heads over to Captain Connelly’s hotel room and the pair sleep together – which has been happening on-and-off for almost two decades. Back at home, Liz looks into Clark’s tattoo and discovers that he got the spiral design tattooed on his chest just four days after Annie died – proving a connection between the two cases. She heads to Evangeline’s house where she shares her discovery and reveals that the DNA results have confirmed that the tongue found in Tsalal was Annie’s. So, the pair agree to work together to solve the case.

Evangeline heads to the Nook after figuring out that Clark had bought a trailer so that he could keep his relationship with Annie a secret and that’s where he would have kept it if he didn’t want anyone to know. Having located the trailer, Evangeline and Liz look around and find Annie’s mobile phone, images plastered on the wall above the bed and a spiral symbol on the ceiling.

Liz and Evangeline are urgently called to the ice rink where the frozen bodies have begun thawing, in turn revealing that there are only six bodies and Clark’s is not one of them…

Evangline watches on as Julia’s body is cremated. At the hospital, Liz speaks to Otis to find out if he knew Clark from before. He reveals that he had been aware of the research station in Tsalal but didn’t know the men there.

Otis shares that Clark said “she’s awake” – alarming Liz as it triggers a memory. Asking about his accident 30 years prior, Otis shares that there was a cave-in and men died trapped in the ice. Otis and a few others ran out, into the blizzard, to get help but suddenly there was a screaming sound and all the men started following after it. The next morning Otis woke up in the hospital with his injuries but no idea how he sustained them. He points out the cave system on the map, warning Liz that she can’t go alone as the whole system has collapsed.

Liz tells Evangeline she’s found the entrance to the cave system – thanks to Otis – so they drove over to check it out. During the drive, Evangeline asks after Leah with Liz saying she’s turned into “one of those crazy radicals”. They arrive at the cave to find someone has sealed the entryway shut. Having been kicked out by Kayla, Peter asks his father if he can stay with him for a while. Leah participates in a protest at the mine, with the troopers called in when things turn violent.

Evangeline sees a vision of Annie amongst the crowd which causes her to lose her focus before she’s snapped into the present when she spots Leah being attacked by one of the troopers.

Back at the station, Liz receives a call from Captain Connelly telling her to report to Kate’s offices to discuss the protest. Evangeline takes Leah to the station so she can be booked – as per Liz’s instructions. Peter shows Liz what he’s found – the LLC that funds the research station traces back to Tuttle United who also have links with Silver Sky mining.

Liz arrives at the mine to meet with Kate and Captain Connelly. Having thought she was there to talk about the protest, she soon discovers that what they’ve really called her there for is to review some CCTV footage which shows Evangeline and Liz at the entry to the cave - which happens to be on Silver Sky land. Liz tells Kate and Captain Connelly about the intel they got from Otis but the forensic results are in – they’re putting it down to a weather event. Liz refuses to believe that the scientists froze to death, telling Connelly about the link between the Annie K case and scientists but he’s having none of it. He tells her that the case is closed and to go home.

Kate tells Hank that Liz is looking for the location of Annie’s murder and that she “can’t find that cave”. It is clear Hank has covered things up for Kate in the past and once again, Kate is counting on him to sort this out.

Evangeline continues seeing things whilst at the laundrette. Qavik’s friend reveals that stones with a spiral symbol were often left out as a warning to hunters and that they were placed in areas where “the ice would swallow them whole”. Evangeline rushes back to the station to speak with Liz where she’s informed that the case is over and that Captain Connelly knows about what happened on the Wheeler case.

Out on the ice, Rose smashes through so that Evangeline can pour Julia’s ashes into the water. A vision distracts her and causes her to almost fall in but Rose manages to get to her in time and pull her to safety.

Liz calls Peter into her office and challenges him to ask questions about Wheeler – the final case that she and Evangeline worked together. He point-blank asks her if they staged it to look like a suicide but she refuses to answer, instead giving her the keys to her shed so he can stay there instead of with Hank.

Liz brings Otis to her house so he can show her where the caves are and in return she gives him drugs she took from the evidence room. Hank arrives to arrest Otis but when Liz refuses to let him leave he pulls his gun out and shoots Otis dead. Peter emerges from Liz’s shed having heard gunshots to find Otis dead on the floor and Hank with his gun pointed at Liz. Hank confesses to moving Annie’s body before raising his gun to shoot Liz but Peter stops him by shooting him in the head. Evangeline enters the house to find Hank and Otis dead on the floor and comes up with a cover story. Peter agrees to clean up the house, so that Evangeline and Liz can head to the caves.

Liz and Evangeline head to the ice caves. Evangeline squeezes through a small gap having had a premonition that it’s “this way”. The pair make their way through the tight cave but come to a dead end. Evangeline is adamant they’re in the correct place but suddenly she falls through the ice to the cavern below. Just as she’s about to go get help, Liz falls through the ice too and suddenly they’re both stuck.

But then Clark suddenly appears behind them and the pair follow after him, discovering an underground lab. They find a hidden exit behind some shelves and make their way up the ladder and through a hatch which opens straight into the Tsalal Research Station. Liz and Evangeline split up to try and find Clark but Liz finds herself getting locked in the freezer by Clark. He then heads into the corridor and hits Evangeline over the head with a fire extinguisher. Having broken out of the freezer, Liz finds Evangeline beating up Clark.

Back at Liz’s house, Peter gets to work cleaning up the crime scene and hiding any evidence. Leah arrives at the house ready to spend New Year’s with Liz and is surprised to find Peter there cleaning but he uses the situation with Kayla as an excuse as to why he’s acting strangely and the pair leave so he can drop her back to Kayla’s.

Liz and Evangeline tie Clark to a chair so they can interrogate him. Evangeline puts headphones in Clark’s ears and puts the video of Annie’s last moments on a loop so he has to listen to it over and over. After sufficient time has passed, they remove the headphones and ask Clark if “he was there”. He says that Annie started to piece together what they were doing, revealing that the microorganism they were digging for did work because the pollution from the mine helped soften the permafrost which meant they could extra the DNA with much less damage. The scientists encouraged the mine to release more pollutants – as it created a better environment for their work – despite knowing that the polluted water was causing deaths amongst the local community.

Asking what happened to Annie, Clark shares that she had destroyed all their work in their lab after finding out what was going on and that he ran downstairs after hearing her screams to find Lund attacking her. When she began to fight back the other scientists “finished the job”. Clark denies having any involvement in her murder but a flashback shows him suffocating her to death. When Evangeline questions why they cut out her tongue, Clark reveals that wasn’t them.

After a break the pair are ready to continue interrogating Clark so they ask him what happened with the scientists, to which he responds “she killed them”. Clark shares that he kept seeing her and hearing her voice, knowing that she’d eventually come for them. His flashbacks show him hiding beneath the station and holding the hatch shut whilst his fellow scientists screams can be heard in the distance. Clark claims that Annie has been hiding in the caves for years – long before she was born – leaving Liz to walk out in frustration.

Liz wakes to find the research station without power and a dead Clark frozen in the ice after Evangeline let him out knowing that he would kill himself. With the backup generator not working, the pair are left freezing and without light.

Rose gets a visit from Peter who repeats the line that Evangeline told him to say: “Take me to where Julia is”. Liz asks a shaking Evangeline what she’s doing to which she responds: “There is something out there calling me”. Evangeline brings up Holden, which angers Liz as she doesn’t want to talk about her dead child. Having calmed down, Liz returns to find an unresponsive Evangeline walking out towards the water in the thick of a snowstorm. Liz begins to hear her son calling out for her and spots him trapped below the ice, so she hits at the ice and falls through straight into the freezing cold water before Evangeline – having come to from her own vision – pulls her out.

Rose and Peter break through the ice and dispose of the bodies. Evangeline and Liz – having waited out the storm – toast to the New Year but something Evangeline says about holding the hatch sparks a thought for Liz. Rushing into the room where the hatch is, she pours chemicals over the outside of the hatch before shining a UV light which reveals a handprint. This leads Liz to realise they’ve been asking the wrong question – they should have asked “Who knows who killed Annie?”.

They drive over to speak with Beatrice and Blair – cleaners from the research station. They confess to finding the underground lab at the research station and that their community, armed with weapons, went to the research station where they forced the scientists out on the ice, told them to take their clothes off and left them out there for her “to take them”. Evangeline and Liz leave, agreeing that it’s just a story and that the forensic investigation concluded the scientists died from a slab avalanche. As she’s leaving Evangeline asks about Annie’s tongue but Beatrice denies having any knowledge.

Later on, we see Liz being interviewed by police about the disappearance of Hank Prior and Otis Heiss. She delivers the pre-agreed story before being asked what happened with Evangeline, who left Alaska after everything happened. But she did leave behind a video confession from Clark where he revealed all the details about the pollution from the mine – a video which was later leaked and subsequently led to the mine being closed down. Liz denies ever leaking the video or having knowledge of where Evangeline is despite it showing the pair together at Evangeline’s new home out on the water.

True Detective: Night Country available exclusively on Sky Atlantic