This post contains spoilers from Long Bright River episode 8 from this point forward.
Still reeling from the news that Truman could be the killer, the Long Bright River finale opens with Mickey in disbelief. He's the one cop she hadn't considered and the one cop she doesn't believe would do this. She adamant that Truman isn't the killer. Mickey buys suboxone, which Kacey uses to stay clean, from a drug dealer and asks him about a new product Dock has been pushing. The dealer doesn't know who's behind the drug. She only learns that it's blue.
Mickey brings Kacey to her place while Thomas is with Mrs. Mahon, who agrees not to allow Thomas to come home. While getting ready for bed, Thomas hears coughing coming from his house. He's somehow ended up home and wakes Kacey up from a bad dream. He's surprised that she knows him, but she's surprised that he knows her, too — but just as "the girl with pink hair." Thomas shows Kacey his family tree project. He admits that his mom told him that she didn't know who she was. He has more questions than ever.
Later that night as Kacey and Thomas bond, Mickey goes to Truman's house to talk with him, but catches him placing a bag in his trunk and leaving. She follows him to a building and grabs her gun. As Truman injects someone with a needle, Mickey creeps up on him and makes him surrender. The woman he injected starts breathing again, which means he was helping her from an overdose. So, what's the truth?
Mickey loses Truman's trust
Truman continues to treat the woman and calls her an ambulance. Finally, it's time to clear the air with Mickey. Mr. Winton helps people on the street, but since he hasn't been feeling well, Truman has stepped in to take over. Why didn't he tell Mickey? She confesses that Kacey heard from Emily Morris that he was the killer. "So you gain her trust to lose mine?" He's very hurt about her believing that and pulling a gun on him. Needless to say, it's going to take a lot for them to end up together.
Already in a bad mood, Mickey returns home to see Kacey and Thomas hugging with Mrs. Mahon beside them. She's speechless before sending Thomas to get ready for bed. Kacey apologizes, but Mickey still doesn't have anything to say until she takes a shot. She doesn't say anything about Thomas. Mickey asks about Emily's accusation against Truman and the exact words. Kacey says Emily said "partner" and assumed Truman. Lafferty?!
At the precinct, DiPaolo asks Danjarat why he ordered an autopsy on Paula. Meanwhile, Mickey shows Kacey a photo of Lafferty, and she recognizes him as Doc's supplier and has been with a lot of the women sexually. In the photo from their baseball game, Mickey clocks Lafferty, Ahearn, and Scanlon all together. They're high school buddies and seem to be in on this together. When Mickey suggests talking to Danjarat, Kacey shuts down trusting more cops and says they should go to Dock.
Against Kacey's wishes, she calls Danjarat and tells him everything. He and DiPaolo go to Lafferty's apartment, but he's not there. They find massive amounts of insulin in his refrigerator. Danjarat comes to Mickey's door to share that he's fled, but Kacey's missing, too. Mickey leaves Thomas with Mrs. Mahon and gets on the case.
Who is the killer in Long Bright River?
Just like the show's opening scene, a woman leaves her tent, grabs a bite at the convenience store, and enters a car. This time, we see it's Dock driving the car. He calls Lafferty and they discuss an exchange. Mickey returns to the dealer to find Dock, and he sends her to the church. It's super rundown and she notices Kacey's purse in the pews. She calls Danjarat, puts her phone in her pocket, and creeps up on Lafferty and Dock, holding them at gunpoint.
Lafferty claims that he's working undercover and tells her to talk to Ahearn. Mickey's still hesitant about Dock being a good guy, but he tells her that he was the one who took her to the hospital after she was attacked. Mickey's sure they're both lying and threatens that she'll pull the trigger if they don't talk.
According to Lafferty, he didn't intend for any of this to happen. He says the girls turned on him, and while he's talking, Dock warns Mickey to step back. As he's talking negatively about the victims, there's a gunshot. Emily Morris leads a group of women, including Kacey, and shoots Lafferty dead. She puts the gun down and surrenders to Mickey. But Mickey wipes the gun and takes a shot at Lafferty herself. She instructs them all to leave. She notices her phone has died and assumes Danjarat heard nothing.
Mickey goes into questioning and leaves the precinct. Danjarat and Ahearn swap an unreadable look at each other. Kacey picks her up and she explains that the women wanted to do that for themselves, Mickey wasn't supposed to be there. They have the heart to heart they have been needing, and Mickey admits that Simon coming in between them was the starting point of their unfortunate drift. It's catharsis for Mickey, at very long last.
The community holds a memorial for the women who were killed, and the priest calls it "a long bright river of departed souls." Danjarat fills her in on the investigation and how he believes Ahearn's involved somehow but won't talk. Mickey planned to quit but she was cleared because Danjarat overheard the confrontation with Lafferty when she called him. He implores her not to quit because she cares.
Next, Mickey tries to mend fences with Truman. He can't forgive her for pulling a gun on him. She accepts it and tells him that she quit the force before she leaves. As she walks away, he agrees that she was never meant to be a cop; she should have been a music teacher. Mickey picks up Thomas from school and they head to the hospital to visit Kacey and the baby. They have come a long way, but they earned their happy ending as a family.
Watch Long Bright River only on Peacock.