Contains spoilers for this episode and earlier episodes.
Eight researchers vanish from the Tsalal station as Ennis enters its winter darkness. A delivery driver finds the building deserted, with ordinary work interrupted and a severed tongue on the floor. Police chief Liz Danvers examines what the men left behind and gives deputy Peter Prior questions to answer about their lives. The disappearance has no visible explanation, while Raymond Clark announces that something has awakened just before the lights fail.
Trooper Evangeline Navarro sees a possible connection to Annie Kowtok, an Indigenous activist whose murder remains unsolved. Annie's case has divided Navarro and Danvers before, and their renewed argument makes cooperation difficult. Peter retrieves the old file despite his father Hank's resistance. Danvers also struggles with stepdaughter Leah, while Navarro worries about her sister Julia. Their family conflicts continue alongside the inquiry, with the town's mine and Annie's opposition to it part of the history neither investigator can put aside.
Danvers notices that Clark wore a parka associated with Annie, giving the two cases a physical link to pursue. Elsewhere, Rose Aguineau follows a figure she identifies as Travis out onto the ice. She later says that he led her to the missing men, despite acknowledging that Travis is dead. Danvers and Navarro arrive to find frozen human remains emerging from the snow. The discovery turns the disappearance toward a death investigation without resolving Rose's account or the researchers' final hours.