No offence to Aaron Eckhart, but “Sad Aaron” doesn’t quite have the same emotional thwack to the soft parts as “Sad Keanu”. Like John Wick, Muzzle begins with a dead doggie, and Eckhart plays LAPD officer Jake Rosser, an army veteran with PTSD; his only meaningful relationship is with his K9 partner, a German shepherd called Ace. There’s an excruciating scene setting up their deep bond, Rosser musing on the misuse of the word “literally” as he drives to work, Ace listening dutifully in the passenger seat next to him.

When Ace is killed in a shootout, Rosser finds himself embroiled in a police scandal. Footage emerges from the crime scene of him head-butting a paramedic who insists – quite reasonably, you might think – on treating human casualties first. After a few sessions with the police therapist, Rosser is back on the job and out for revenge. His new partner is Socks, an aggressive mutt traumatised by an undercover job which involved her being fitted with titanium teeth.

The point, of course, is that Rosser is as broken as the dog he’s training. The problem for Eckhart is that with his deadly dull performance he is out-acted by his canine co-star. It’s fair to say the uncredited canine actor playing Socks does a better job of channelling damaged vulnerability, with sad eyes peering over her muzzle. Eckhart’s gritted-teeth facial expression – like he needs to get to a loo fast – doesn’t come close.

Muzzle really is a ropey character study, and a pretty shonky thriller to boot, with a bunch of incoherent plotlines muddled in – from Chinese gangsters to the fentanyl crisis and dog trafficking. I have to admit that my opinion of the film dipped even further when Rosser begins a pointless romance with a nurse who lives in his apartment block; this is Mia, played by Penelope Mitchell, who is 23 years younger than Eckhart. The dogs give the film a touch of class, but as a whole this is forgettable.

• Muzzle is released on 14 November on Prime Video.