After his partner is killed in the line of duty, a veteran cop goes rogue to track down the people responsible, ignoring orders and protocol in his pursuit of vengeance. That sounds like the plot to dozens of crime thrillers, both iconic and forgettable, over the past several decades. The difference in Muzzle, written by Carlyle Eubank ’10, is that the slain partner is a dog.

Aside from that, Muzzle follows a familiar path, delivering a lean, tough pulp thriller in the vein of Dirty Harry and Death Wish. Aaron Eckhart brings soul and depth to the role of withdrawn, traumatized cop Jake Rosser, a military veteran. Director John Stalberg Jr. starts with a close-up on Jake in the driver’s seat of his cruiser as he reminisces about the extreme desert heat during his Iraq deployment. It takes a minute or two before the movie cuts to a two-shot of Jake and his partner, Ace, revealing that Jake has been opening up about his past to a dog.

As the movie goes on, it becomes clear that Jake is unlikely to experience the same kind of vulnerability with a human being, even after he begins seeing a therapist and initiates a romantic relationship with his neighbor Mia (Penelope Mitchell), a nurse. That makes it especially horrific when Ace is killed during what appears to be a routine stop of a suspicious vehicle. 

Jake and Ace are called as backup so that Ace can sniff for drugs in the trunk of a car whose driver has run off. After confirming the presence of narcotics, Ace is sent to track the fleeing suspect. Stalberg represents Ace’s perspective in dog-level point-of-view shots, putting the audience alongside him as he carries out his commands.

Ace is shot as he confronts the perpetrator. Jake yells, “Officer down!” as he rushes Ace to the ambulance, but when the responding paramedic tells Jake, “People first,” and turns his attention to an injured human officer, Jake slugs the guy in the face. Jake becomes a pariah, ordered to take leave and undergo counseling.

Jake isn’t satisfied with the official story about Ace’s death, though, and he decides to track the origins of the drugs found at the crime scene. Set on the gritty streets of Los Angeles,  Muzzle uses the fentanyl epidemic and the crisis of the unhoused as backdrops for its action and suspense. Eubank and Stalberg never downplay the importance of those real-world issues. 

They also take Jake’s mental health seriously, and unlike some old-school cop thrillers, Muzzle doesn’t dismiss the value of therapy. “I let anger win a long time ago,” Jake tells the police psychologist. Eckhart effectively conveys his anguish.

When Jake is provisionally reinstated to his position, he gets a new canine partner, one who’s also been through severe trauma. Socks is introduced like any grizzled, menacing figure in a movie, from behind bars with restraints holding her back. She was mistreated by the same drug dealers Jake is pursuing, and she now has titanium implants where some of her teeth were knocked out. In a way, Socks has as much motivation for revenge as Jake does.

Muzzle is tense and violent, especially during its brutal finale, but it’s also a tribute to the bond between people and dogs, with sweet moments between Jake and his animal companions. Jake’s methods may be harsh, but it’s clear that his wrath comes from a place of love.