The Good Daughter Ending Explained: Who Was Zach Culpepper's Accomplice? And Who Orchestrated The School Shooting?

The Quinn sisters were left with more questions than answers heading into the sixth and final episode of "The Good Daughter." 

Episode 5 ended with Samantha (Rose Byrne) and Charlie (Meghann Fahy) back at their childhood home, where they'd uncovered evidence that their late father, Rusty (Brendan Gleeson), might have been secretly funneling money to the Culpepper family for years. But why? And what, if anything, did those payments have to do with the horrific attack that killed their mother, Gamma (Olivia Williams), and nearly claimed their own lives? 

Meanwhile, Kelly Wilson (Shayna Benardo) had confessed to loading the gun used in the school shooting, and security footage appeared to confirm that she'd killed Principal Douglas "Pink" Pinkman (Kovar McClure). But questions remained about who had orchestrated the attack, and whether Kelly had acted alone. 

As Episode 6 begins, the sisters brace for another confrontation with the Culpeppers. Instead, their unexpected visitor is Mason "Huck" Huckabee (Jake McDorman), who has a confession to make.

Huck admits that, at 17, he was the second masked assailant who accompanied Zach Culpepper to the Quinn farmhouse all those years ago. He'd also set fire to their home days earlier. He hadn't intended to burn it down; he merely wanted to scare the prosecutor he blamed for his sister's death.

Anna Lee had died by suicide after Rusty destroyed her credibility on the witness stand in a rape case. Seeking revenge, Huck paid Zach $5,000 to murder Charlie and Sam's father. But everything went horribly wrong when they arrived to find Rusty wasn't home. Instead, his wife and two young daughters were there. Zach murdered Gamma and raped Charlie, while Huck, attempting to wrestle a gun away from Zach, inadvertently shot Sam. Believing she was dead, Huck dragged her into the woods and abandoned her in a river.

In the present day, Huck insists that he tried to stop Zach from assaulting Charlie, but she has no sympathy for him. "He was the weapon that you loaded!" she tells Huck. "Everything that Zach did that night happened because you pointed him in our direction."

Huck also reveals the origins of the Culpepper payments. His parents arranged to pay Zach Jr. $2,000 per month to keep Zach Sr. quiet about Huck's involvement, with Old Sheriff Coin helping orchestrate the cover-up. Daniel Culpepper had been wrongly implicated in the attack, while Huck escaped prosecution — and, in turn, death row. 

Huck only learned about the arrangement roughly a decade ago, shortly before his mother's death. He subsequently confessed to Rusty, who refused to put his daughters through another traumatic legal ordeal. Instead, Rusty took control of the payments and demanded a written confession... but he never forgave Huck. He intended for Sam and Charlie to eventually decide whether to continue protecting him or turn his confession over to the authorities. 

For now, the sisters choose a third option: They alert authorities to Huck's involvement in disposing of Ely Wilson's gun, the weapon used in the school shooting that killed Pink and Emma, potentially exposing him to 10 years behind bars while they consider what to do about his other crimes.

Charlie ultimately doesn't want to pursue the decades-old case — and there's a scenario where they don't have to pursue it. Sam explains that they can stop paying Zach Jr., let Zach Sr. come forward, and decline to voluntarily assist prosecutors. But could it really be that simple, Charlie wonders? "It will be if you're not in Pikeville anymore," Sam answers.

Later on, Sam realizes that although Kelly Wilson was holding the gun during the school shooting, the security footage never conclusively showed her pulling the trigger. And when the sisters, along with Ben (Michael Dorman), revisit the footage, they notice two different hands on the gun and begin to suspect that Pink's wife Judith (Paula Malcomson) was responsible.

Charlie confronts Judith at her home, secretly recording their conversation while Sam and Ben listen from outside. Judith admits that she discovered her husband having sex with Kelly, who subsequently became pregnant. When Judith confronted him about the pregnancy, he informed his wife that they would raise the baby together, and that she would quit teaching to care for it.

After years of feeling controlled and diminished by her husband, Judith decided to kill him. She manipulated Kelly into believing Pink intended to force her to have an abortion, convincing the teenager to bring her father's gun to school... but Kelly froze when the moment came.

"I stood behind her," Judith confesses. "I wrapped my finger around hers, and I pulled the trigger."

Judith fired repeatedly, intending to emerge as the grieving widow and heroic teacher who stopped the shooting, then collect Pink's life insurance money. Emma's death, however, was accidental: Kelly refused to relinquish the gun, and it discharged during their struggle. Judith never intended to leave Kelly alive, either: "I was gonna shoot her in the head... but I ran out of bullets."

After realizing Charlie is recording her, Judith retrieves another gun from her kitchen drawer and delivers one final confession: "I, Judith Hiller, murdered Douglas and Emma. I pulled the trigger six times. Kelly is innocent." Judith then orders Charlie outside before dying by suicide. Ben rushes to comfort his distraught wife, who cries, "I couldn't save her!"

With Judith's confession secured, Sam negotiates a reduced sentence for Kelly, leveraging what she knows about the sheriff's department's decades-old misconduct in the Culpepper case. Kelly accepts five years in prison, with her mother, Ava, agreeing to raise her baby until she's released.

As for the Quinn sisters, there's hope for a happier future. Charlie and Ben reconcile after finally opening up about her past trauma, his infidelity, and their struggles to have children, and Ben asks her to move with him to Atlanta. Sam, meanwhile, agrees to someday tell Charlie more about her late husband Anton.

While sorting through Rusty's belongings, the sisters discover the photograph of Gamma he'd wanted them to find, hidden behind the framed picture he'd had Sam bring with her to the hospital on the night he died. On the back is a message: "LAST WORD." Their father finally figured out how to have the last word! And as Charlie picks up another old photograph of the sisters before tragedy struck, they're transported back to happier memories of their mother, and the family they once were.

What did you think of "The Good Daughter" finale — and of the Peacock miniseries as a whole? Grade the show via the following poll, then leave a comment with your full review.