Last night, The Sinner, a limited series based off the book of the same name ended. There’s been eight episodes and I’ve been watching since it started and obsessively waiting for answers. For anyone who hasn’t seen it, here’s the premise of the show.
Full Recap

Cora Tannetti, mother and wife, kills Frankie Belmont on the beach with multiple witnesses. But the mystery is that no one, including Cora, knows why. For most of the season, we follow Detective Harry Ambrose as he tries to uncover the truth. More specifically, he tries to figure out why she becomes violently triggered by one song (note: it’s the song that’s playing when she stabs Frankie on the beach). Along the way, we see parts of Cora’s religious past as well as flashes of a fourth of July weekend gone wrong. However, there’s a two-month time period where Cora can’t remember anything. But after eight episodes of flashes and utter confusion, we finally know what happened to Cora. More specifically, the trauma that’s caused her to kill someone on the beach.
It starts when Cora takes her sick, younger sister, Phoebe to meet up with her always-creepy boyfriend, JD, and his friends. Which also includes his ex/other girlfriend, Maddie. Eventually, they all leave to go to the Beverwyck, a very exclusive country club. It also happens to be hidden behind the woods where they later find Phoebe’s skeleton. Here, we meet for the second time in the season, Frankie Belmont, the guy Cora killed on the beach.
What Happened to Phoebe

At the Beverwyck, Phoebe, and JD bond. I’m not quite sure what they bond over, perhaps it’s just their sarcastic nature or it’s just Phoebe’s desperation to lose her virginity. While they talk, JD takes his and Cora’s relationship to the next level. By that, I mean that he makes a business deal with his business partner. The specifics of it are unclear, but it does allow his business partner to add onto the horrendous polyamorous relationship they’re having with JD’s ex, Maddie. But of course, Cora doesn’t realize what’s going on at first, so she just smiles and agrees with everything he says.
Then, they go back upstairs where she finds Phoebe and Frankie dancing in another room. Then, at some point, they all agree to go downstairs and hook up all simultaneously. As Cora’s in the middle of having sex with who she thought was JD, she sees her sister’s arm hanging off the side of the couch. Plus, Frankie’s trying to resuscitate her and breaks a rib in the process. Turns out, he accidentally kills her, or maybe she died from the ecstasy pill she took earlier that night. Either way, it doesn’t look good for Cora, who went after him on the beach.
How the Season Ends

After that, Cora suffers a two-month lapse in memory. But in her defense, she did get drugged by someone wearing a ski mask. Then, Ambrose needs to figure out why. Turns out, JD blackmailed Frankie’s dad into getting her to forget everything. But initially, Frankie’s dad just wanted to help her heal from her injuries.
Overall, Jessica Biel, who plays Cora, did a beautiful job of playing the guilty innocent. She’s guilty of killing Frankie but still maintained a sense of naivety from the internal struggle she had within. There were times when there wasn’t much information but just enough hints (via flashbacks) to keep the audience enticed. The story played out in a way that didn’t fully reveal itself until the last couple episodes. And that only made it all that much more intriguing.