1968. A group of teens is driving to prom discussing the merits of Frankie Valli vs. Mick Jagger. One girl, Ada, feels guilty about leaving behind one of their friends. One of the other girls replies that she was a slut and didn’t deserve to go with them. As they cross under a bridge, above them a woman lets go of a cement block, which crashes onto the car (this was what Episode #2 ended with, for those paying attention). The car pulls over, and the teens get out screaming. Ada lays there with a bloody head wound, seemingly alive but gone at the same time…
Present Day. Ada lies comatose in bed. A distraught Brenda leans over her, saying she’d switch places with her in a second. Seems that Brenda was somehow involved in the car accident that we saw.
At the funeral, Robin weeps over Justin’s body. Elsewhere, Ronald, the mayor of Waterbury, announces that Heather Peterson has been arrested in Justin’s murder. They also believe Heather is connected to the death of Verna McBride. Sarah is skeptical that Heather is the one who committed the murders, but Dylan tells her she’s beginning to sound crazy.
Sonya (the other woman, along with Brenda, that seems to have defied the aging process) stops by the nursing home where Brenda is talking to Ada. She tells Brenda that her efforts are futile, since Ada can’t hear her, and criticizes Brenda for not being there for Ada in the past. Brenda leaves angry, saying it’s a shame the hunk of cement didn’t take out Sonya instead. Ah, so Sonya was the driver of the aforementioned car, and the person she was badmouthing must have been Brenda.
Trent McBride shows up at Robin’s office and tells him that Justin gave him a bad check. Robin is unaware of the deal, saying Justin usually made all of the business decisions. Trent replies that he better get a new check by tomorrow and leaves.
Brenda is drinking her sorrows away at a bar when Sonya’s husband (and the mayor of Waterbury) Ronald approaches. They begin to reminisce, and soon they’re about to have sex in a hallway. Ronald tells Brenda she’s as beautiful as when they were teenagers, and Brenda becomes upset. She composes herself and leaves, insulting Ronald’s manhood on the way out.
A creepy man stops by the art gallery and notices Sarah’s painting of the Executioner. He’s very interested in purchasing it, but Sarah tells him it’s not for sale. He decides to get something else instead, but Sarah’s still a little freaked out. Later that night, Sarah calls Dylan from her home because she feels jumpy after the murders. Outside, a man wearing leather gloves waits outside the house. A police officer sits outside of Sarah and Dylan’s house, watching a video on his tablet, when suddenly a pair of gloves reaches through his window and begins to strangle him. Guess who’s back!? Waterbury’s favorite serial killer, The Executioner! Inside the house, Sarah receives a series of phone calls, but no one is on the other line. She says she’s going to go outside to the police officer, when a voice finally answers, calling her “brave, stupid Sarah” in a mocking tone. She hangs up, but calls the number back and hears a phone ringing inside the house!
Suddenly, the Executioner comes racing down the stairs. She runs to the front door and opens it, seeing the body of the police officer outside. The Executioner catches her by the hair and throws her to the ground. She escapes up the stairs and hides in a closet. The Executioner tries to open the door, but Sarah manages to hold it shut until he leaves. Sarah hears Cam calling for her, and he finds her in the closet. He notices the open window next to her, where the Executioner may have made his escape.
More police arrive. The officer who had been attacked is receiving medical attention, while Vaughn and Cam speak with Sarah, Brenda and Dylan. The phone calls came from Verna McBride’s cell. Vaughn still insists that it’s not the Executioner, but regardless Sarah doesn’t want to stay in the house anymore
Sarah meets with Robin the next day and says he should leave town as well. He doesn’t see how that’s possible considering everything he has going on. He still wonders why Justin was murdered, and after some prodding from Sarah, he remembers something: A family had been living in a shack on the spot Robin and Justin eventually built their home. Said family ended up squatting in an abandoned house without heat or electricity. They used a propane heater as a makeshift furnace and suffocated to death. But Robin doesn’t understand how Justin could be responsible for their deaths, as he didn’t intend for any of that to happen.
Dylan informs Alison that he’s leaving town. She encourages him to stay as the Executioner story is just now getting national attention, and a story like this only comes around once in a lifetime. Dylan feels conflicted - he wants to support Sarah, but this could be a professional opportunity he'll never get again. Dylan returns home and tells Sarah that Alison wants two weeks’ notice, and that he can’t leave just yet. Sarah is angered by the news, and she and Brenda hop in to their car and drive away, leaving Dylan on the street.
While Sarah drives, Brenda suggests that maybe there are other men who might be a better fit for her, like Cam. Sarah replies that Cam is married and the conversation is ridiculous, but Brenda says that Cam is clearly interested in Sarah. Just then, a black pickup truck swerves toward them, and they go off the side of the road. Sarah thinks it’s the Executioner and the car won’t start up again, so Brenda pulls out a gun (we love that she packs heat). She runs back to the road and fires a few shots at the truck before it speeds away. Brenda and Sarah walk back to the town. Sarah suggests that the Executioner is trying to kill her because she once tried to kill herself and that’s a sin. Brenda says that she’s the one with the greater sin and reveals that Ada’s in the nursing home because of her dropping a brick on her head.
Brenda wasn’t one of the teens in the car with Ada; she was the girl who dropped the cement block! She was aiming for Sonya and missed. And to top it off, she was pregnant with Ronald’s baby, meaning that Ronald is Sarah’s grandfather. Well, guess that explains why Sonya was badmouthing her. Sarah tells Brenda that she has to confess, but Brenda says she refuses to go to jail for a mistake.
Robin discovers Justin was stealing from his clients and that he now owes $2.8 million. Robin’s lawyer says that if he sells all of his properties, he may come close to breaking even, but Robin is hesitant to sell everything that they built their lives upon. The lawyer also reveals that Justin had the land for their home rezoned before they purchased it, effectively screwing over the family who had lived there due to the tax hikes. Super shady, Justin. Also, totally the reason he was killed for the sin of Gluttony.
Back in the woods, Sarah discovers Brenda is no longer behind her. She has gone off to find the Executioner, but he finds her first and grabs her from behind. Sarah finds Brenda’s gun, but not Brenda. Brenda is chained to a cement block in a boathouse. The Executioner walks in and she confronts him, but he simply walks over to the block, picks it up and tosses it in the water. The block sinks to the bottom of the lake, dragging Brenda with it. The Executioner watches as Brenda drowns.
Eventually, Sarah finds the dock where she sees Brenda’s body floating in the water. Bye, Brenda. The ambulance arrives and Brenda’s body is carted away. June Henry (Cam's wife) checks out Sarah, when Cam walks over and gives Sarah a hug, clearly irritating June. Sarah vows to find and kill the Executioner for what he’s done.
Robin arrives at Trent’s cabin (presumably to give him the monies Justin owed him), but he doesn’t appear to be home. As he’s leaving, he notices a shack behind the cabin. Inside he finds a bunch of creepy taxidermy creations as well as sharp knives and other tools. Trent pops up from behind him, hands bloody, proudly declaring that he killed all of the animals himself. Robin is freaked out and says he’ll come back another time.
Vaughn and Cam release Heather from custody since she couldn't have killed Brenda since she was in jail. Sarah reveals Brenda’s confession to Sonya, and that Ronald may be her grandfather. Sonya is shocked, but says she can’t possibly by Ronald’s granddaughter. Regardless, Sarah says she’s going to the chief of police to tell her what she knows.
But first! Sarah goes to see Tom Winston who says he’s sorry for her loss. Sarah says the punishment for envy is drowning and that Brenda was the most jealous person she ever met. Tom says at least Brenda was able to confess and get some degree of relief. Tom expresses concern that Sarah could have been killed in the woods, but Sarah says she thinks she’s not a target since the Executioner has had multiple opportunities to kill her and never did. Tom replies that the Executioner is blinded by the greatest of sins: pride.
Back at his shack, Trent smokes a cigarette while loading his rifle…