(Credit: Netflix)

The 2003 neo-noir drama Mystic River often gets passed over in discussions about the best film directed by Clint Eastwood, as a movie which fails to offer up the punch and panache of his more celebrated grit-and-grizzle westerns and anti-heroic thrillers. Yet it shows the director at his most ambitious, adding stylistic nuances to his no-nonsense approach in ways few of his other works can match.

He excels at striking a careful balance between the forensic realism of a contemporary murder mystery, the heart-rending tragedy at the intersection between each thread of the story, and the seedy underbelly of the world its characters inhabit. There’s his decision to present the film’s inciting incident, the murder of teenage Katie Markum, via an overhead shot of her abandoned car from the perspective of a police helicopter, soundtracked by a call made by two young boys to the emergency services. And the quiet power in protagonist Jimmy Markum’s silent realisation that his childhood friend is deceiving him, on the steps of his front porch, with the less-is-more acting of Sean Penn’s Oscar-winning performance letting the camera do the work.

“Do you ever think about how just one little choice can change a whole life?” Markum asks Sean Devine, in the hours following his daughter’s death. He’s referring to a moment 25 years earlier when the two of them allowed their friend Dave Boyle to get into the car of two strangers posing as police officers. For most of the film’s slightly overlong two hours and 15 minutes duration, Boyle’s kidnapping, torture and rape as a child at the hands of these two strangers and Katie Markum’s murder are inextricably linked.

We see Boyle spotting Katie at the bar he happens to be drinking at shortly before her disappearance. He arrives home bloodied in the middle of the night, claiming to have gone “fucking nuts” on a mugger in the car park. Despite his wife Celeste noticing inconsistencies in his story, the two of them withhold this information from both the police and Jimmy Markum, until it becomes suspicious.

In a late-night confrontation, Dave directly links Celeste’s own suspicions of him in relation to Katie’s death to his childhood trauma. “Once it’s in you, it stays,” he tells her ominously. “Did you know there were child prostitutes in Rome Basin?” he adds, seemingly implicating himself in acts of paedophilia.

But what makes Jimmy suspect Boyle?

As Sean’s fellow police detective, Sergeant Powers, observes, “Boyle fits the profile” of someone who’d murder a teenage girl. “Mid-30s, white, marginally employed, sexually abused as a kid.” Jimmy ends up agreeing after Celeste tells him about her husband’s condition when he came home on the night of Katie’s killing. He and his heavies get Boyle drunk and take him to the bank of the titular river, where they force a confession out of him under pain of death. Jimmy sticks a knife into his childhood friend, believing that he is avenging his daughter’s murder.

At the same moment, Sean and Powers discover a key detail they missed earlier in their investigation, upon listening to the 911 call which led the police to Katie’s car. The boys in the phone call mention “her”, even though Katie’s body wasn’t anywhere near the car when it was found, revealing that they must have been involved in her disappearance.

They use the call to track down the real killers, exonerating Boyle. Tragically, though, it’s too late to save him. “Thanks for finding my daughter’s killer, Sean,” Jimmy tells him when they meet the next morning. “If only you’d been a little faster.”

Who were the killers, then?

Aside from Boyle, the other suspect Sean and Powers identify early on in their investigation is Katie’s secret boyfriend, Brendan Harris. Harris’ family has a history with the Markums since Brendan’s father, Ray, ratted Jimmy out to the police while the two were working together in the same criminal gang. And Ray’s gun turns out to be the weapon that killed Katie.

But Ray hasn’t been seen for decades. In fact, Jimmy killed him and disposed of him in the Mystic River, just as he does with Dave in the course of the film. And Brendan appears to have been in love with Katie, is genuinely horrified and distraught at her murder, and passes a lie detector test to prove it.

Nevertheless, the link between the murder weapon and the Harris family proves to be decisive, when the 911 call is also traced to their address. Brendan and the police reach the same conclusion at the same time. It was his younger brother Ray Jr and Ray’s friend John O’Shea who killed his girlfriend.

And what was their motive?

We see Ray Jr, known as “Silent Ray” due to his inability to speak, encouraging Brendan to get over his grief for Katie at one point in the movie, telling him that he’s better off without her. This scene suggests that he may have had some grudge against his brother’s girlfriend. Not least because their mother Esther Harris, we later find out, may be aware that Jimmy has murdered her husband and is buying her silence with a forged alimony payment every month.

Still, it’s not clear how much of this backstory Ray Jr, a young teenager, is aware of. And we don’t see enough of him in the film to be convinced that he’s capable of murdering in cold blood. When Sean relays the young killers’ confessions to Jimmy, he explains “they don’t know” why they killed Katie. They were playing with the gun in the street when her car approached, and it “went off” by accident. They brutally beat her to death with a hockey stick and hid her body in order to cover up what they did.

Their actions were just as barbaric as a premeditated murder in the end, but were driven by fear rather than any calculated motive. Just as Jimmy compares his own life to Dave Boyle’s on the basis of Boyle’s chance decision to get into a car as a child, the happenstance of Katie getting into a car and driving to her boyfriend at the very moment two kids were messing around with a gun outside is ultimately the key to her fate.

The Mystic River of the title, which flows through suburban Massachusetts and into the Boston Harbour, serves as a metaphor for the unpredictable ebbs and flows of people’s lives. Fate can be determined after the fact by scientific explanations, such as those put forward by forensic experts in a criminal investigation, yet it is essentially mysterious and unknowable. The only certainty the film leads us with is that, too often, one tragic fate leads to another.