Contains spoilers for this episode and earlier episodes.
Maddy's body gives the investigators another paper letter and injuries connecting her death to Laura's killer. Cooper asks Truman for time to finish the case before notifying the families. Donna leads him back to Mrs Tremond's house, only to find a different woman who denies the earlier encounter. She nevertheless passes on pages Harold left for Donna. Laura's account describes a dream matching Cooper's red room vision. Meanwhile, Catherine pressures Ben to surrender the mill and Ghostwood holdings in exchange for her alibi. Donna visits Leland and comes dangerously close to another attack before Truman arrives to bring him into the inquiry.
Cooper gathers the suspects and several townspeople at the Roadhouse, hoping an unexpected connection will reveal the answer he has forgotten. The elderly waiter offers gum, and Leland's recognition of it brings Cooper's dream back into focus: Laura named her father. Cooper returns to the station pretending that Ben remains his suspect, then locks Leland in the interrogation room instead. BOB speaks through him and admits the killings. When the sprinklers activate, Leland fatally wounds himself against the door and regains awareness of what he has done. Cooper holds him and guides him toward a final vision of Laura. Leland dies, leaving the officers with the answer to the murders and questions about the evil that inhabited him.