Vermilion Parish, Louisiana, January 3, 1995. State homicide detectives Martin "Marty" Hart and Rustin "Rust" Cohle investigate the murder of a prostitute, 28-year-old Dora Lange, found in a sugarcane field outside of Erath. Her corpse is positioned against a tree as if in prayer, her head is crowned with deer antlers, and her body is surrounded by twig latticeworks closely resembling Cajun bird traps. Hart and Cohle turn to a five-year-old missing-persons case of a child named Marie Fontenot. Around the same time, another child claimed to have been chased through the woods by a "green-eared spaghetti monster." At the insistence of his wife Maggie, Hart invites Cohle to dinner, but is infuriated when Cohle arrives drunk. While following up on the Fontenot disappearance, they discover another twig latticework, ostensibly placed in recent times, inside her dilapidated playhouse.
Seventeen years later in May 2012, Hart and Cohle are separately interviewed about the Lange investigation by detectives Thomas Papania and Maynard Gilbough. Hart and Cohle have not spoken since an altercation in 2002. The crime scene of a recently slain woman closely resembles the Lange murder scene, suggesting that despite Cohle and Hart's claims of apprehending the killer in 1995, the killer may remain at large.