Mystic River recap

As boys on a Boston street, Jimmy, Sean, and Dave were friends until Dave was abducted and abused by men posing as police, an event that scarred him for life and split the three apart. Decades later they are pulled back together when Jimmy's nineteen-year-old daughter Katie is murdered, and Sean, now a state homicide detective, catches the case. Suspicion falls on Dave, who came home bloodied and shaken the night Katie died and whose frightened wife, Celeste, begins to believe he is the killer. But the truth is that Dave did not kill Katie: the blood was from his killing a child molester he stumbled on that same night, his own buried trauma erupting into violence. Katie was actually killed by two neighborhood teenagers, one of them the younger brother of her secret boyfriend, during a reckless confrontation with a gun that spiraled out of control. Before the real killers are caught, Jimmy, convinced Dave is guilty, murders him and dumps his body in the Mystic River, only to learn moments later that he has killed an innocent man.

The story opens with three boys, Jimmy, Sean, and Dave, growing up on the same working-class Boston street. One day a car pulls up and two men posing as police officers take Dave away; he is held and abused for days before he manages to escape, an ordeal that leaves him permanently damaged and quietly fractures the friendship among the three. Years later they have grown into very different men: Jimmy is an ex-convict who has gone straight and runs a corner store, Sean is a state police homicide detective who left the old neighborhood, and Dave is a haunted family man still living with his childhood wounds. Their lives are violently pulled back together when Jimmy's nineteen-year-old daughter, Katie, is found murdered, and Sean is assigned to the case. The killing reopens old bonds and old suspicions among the three former friends and their families, setting in motion an investigation that will reach back into the neighborhood's buried history.

The investigation into Katie's murder is resolved when Sean and his partner establish that she was killed by two local teenage boys, one of them the younger brother of Brendan Harris, the young man Katie had secretly planned to run away with. The boys had been playing a dangerous prank with an old handgun; it went off, and they chased and beat Katie to death, their resentment of Brendan's plans feeding the violence. The gun traced back to Brendan's long-vanished father, whom Jimmy had secretly murdered years earlier for informing on him, an old sin that circles back into the present. Meanwhile Dave, wrongly suspected, is doomed by circumstance: he had come home covered in blood the night of Katie's death, but from killing a child molester he found preying on a boy, not from harming Katie. His wife Celeste's fears reach Jimmy, who, certain Dave is guilty, lures him to the riverbank with his brothers-in-law, coerces a false confession, kills him, and sinks his body in the Mystic River. Only afterward does Sean tell Jimmy that the real killers have been arrested. Jimmy is left knowing he murdered his innocent, damaged childhood friend, the same friend who as a boy was taken in the car while he was not. The book closes on the three men's ruined bond: Sean tentatively reconciling with his estranged wife, Jimmy shielded and justified by the loyal Annabeth, and Dave gone, his death an unpunished secret carried by the survivors.