Former Louisiana State CID partners Martin Hart and Rustin Cohle give separate statements to a pair of investigators about the murder of a prostitute, Dora Lange, 17 years earlier. As they look back, details of the crime, replete with occult overtones, are accompanied by insights into the detectives’ volatile partnership and personal lives.

A violent denouement in the forest clears the Dora Lange case and turns Cohle and Hart into local heroes. Each man settles into a healthier rhythm of living as Hart returns to his family, and Cohle starts a relationship while gaining a reputation as a closer in interrogations. As time passes and his daughters grow older, Hart faces new tensions and temptations, and Cohle learns from a double-murder suspect that there could be much more to an old case than he'd once thought. In 2012, Gilbough and Papania put their cards on the table, presenting new intelligence that threatens Cohle and causes Hart to reassess everything he thought he knew about his former partner.

Maggie reveals Cohle's activities in 2002, when his relationship with Hart fractured and he quit the force.