The Ending Of The Sinner Season 3 Explained

USA's crime drama The Sinner wrapped up its third season in March 2020, but it's a much different show than it was in season 1. The Sinner was originally imagined as a limited series lasting one season, telling the story of Detective Harry Ambrose's (Bill Pullman) investigation of a woman named Cora (Jessica Biel) and a seemingly random murder she committed.

But the first season did well, and USA reimagined it as an anthology series. Since then, seasons two and three have each involved a new murder case, but they've also delved into Harry's wreck of a personal life and his many, many demons. (There's a reason the show's called The Sinner.)

While the first two seasons forced Harry Ambrose to confront his failed marriage and his relationship with his mentally ill mother, season 3 delved even deeper into who Harry is as a person, on a primal level. The season begins when two friends, Nick (Chris Messina) and Jamie (Matt Bomer) get into a car accident, and Nick is killed. Harry quickly realizes that Nick's death wasn't entirely accidental. As Harry investigates Jamie, he learns that Nick had spent years breaking his friend's mind, pushing Jamie to more and more destructive behavior. Harry tries to help Jamie, but then Jamie starts pushing Harry the way Nick pushed him. The big question in season 3 is, can Harry save Jamie and walk away unscathed in the process? 

And the short answer is, "Nope, not even close."

Season 3 is all about Harry's struggle to be the person he wants to be in spite of all his flaws. The season introduces two new characters: Harry's formerly estranged daughter Melanie and his grandson Eli. When the season begins, Harry and Melanie have made a fragile reconciliation, and Harry is starting to have a relationship with Eli.

Harry's personal struggles are similar to the ones Jamie is going through. At the time of his car accident, Jamie's wife is very pregnant, and Jamie is beginning to crack under the pressure of his impending fatherhood. Harry can sympathize with these struggles. As an investigator, Harry tends to get too personally involved in the cases he investigates, but this time, he goes even farther. Harry could have arrested Jamie many times during season 3. Instead, he tries to help Jamie accept his responsibilities and turn away from Nick's influence.

It's a dangerous game. Nick, a devotee of nihilist philosopher Friedrich Nietzsche, had spent years convincing Jamie to reject society's rules and give in to his basest instincts. Jamie was always conflicted, but the accident pushed him over the edge. As Harry pushes Jamie to do the right thing, Jamie pulls Harry to the dark side.

In his efforts to provoke Harry, Jamie goes after Harry's loved ones, threatening to kill Eli, Melanie, and Harry's new girlfriend, Sonya. In the season finale, Jamie kidnaps Eli and holds him at gunpoint, taunting Harry to do something about it. Harry manages to disarm Jamie, but Jamie keeps provoking him until Harry finally shoots him, which only gives Jamie what he wanted all along. 

But actually, things aren't so simple. Jamie quickly learns that he doesn't actually want to die and that he's maybe not the Nietzschean superman he thought he was all along. Jamie immediately becomes terrified of his impending death and begs Harry to call the paramedics, which Harry does. They arrive too late to save Jamie, and he dies with Harry trying to comfort him. 

When Harry pulled the trigger on Jamie, he wasn't defending himself. He was momentarily giving in to the desire to be rid of Jamie once and for all. Doing so violated one of Harry's fundamental rules as a police officer. Nobody else witnessed the killing, but Harry will always know it was unjustified. 

That's bad enough. Even worse, Jamie's reversal destroys any reassurance Harry might have had in the killing. In one moment, Jamie's philosophy is revealed to be a sham. But the moment comes too late for Harry to avoid his terrible mistake. 

Harry Ambrose's future looks grim. The Sinner is an anthology show, so the upcoming season 4 will have a whole new case. But like the first three seasons, it will no doubt have parallels to whatever's going on in Harry's personal life.

The specifics of season 4's murder case are anyone's guess, but Harry's personal life is a lot clearer. When season 3 began, Harry was living in an isolated cabin. Building a relationship with his grandson was one of the few things tying Harry to the rest of humanity. Melanie had already decided to cut Eli's contact with Harry before Jamie kidnapped him. Based on the events afterward, it's unlikely Harry will see much of his daughter or grandson in season 4. 

The other main relationship in Harry's life is his budding romance with Sonya, which does remain intact through the season 3 finale. Unless the show adds more characters, Sonya is currently the only positive influence in Harry's life. That's going to put a strain on anyone's relationship, especially someone with as troubled a romantic history as Harry's. While Harry has made progress in earlier seasons, it looks like season 4 could see him at his lowest point yet.