Two years ago, an unidentified man drove a Mercedes through a crowd of people waiting for a job fair. Detective Bill Hodges (Brenan Gleeson) vowed to find him. He didn’t. Burnt out and traumatised, Hodges retired. The killer, Brady Hartsfield (Harry Treadaway) didn’t.

Adapted from the first Bill Hodges novel by Stephen King, Mr Mercedes is the textbook example of how to adapt a book for the screen. The writing staff, including TV legend David E. Kelley and superlative crime novelist Dennis Lehane, never lose sight of the fact this is a character study of two differently broken people. Bill is a man who’s staked his entire life on a belief in justice and the law. Brady is a man born into a horrific family whose only recourse was to assume there is no law. Neither is remotely functional, but where Brady wallows in his awfulness, Bill tries. Then swears. Then tries again.

The writing really is top notch here, in ways you don’t notice until a few episodes in. This is a tiny case in scope that’s massive in consequence and Bill’s dogged pursuit of the truth puts us on the trail with him for every step. The car matters. How Brady got it matters. The consequences for the owner matter. Bill’s friends Jerome (Jhasel Jerome), Holly Gibney (Justine Lupe), Peter Dixon (Scott Lawrence), Janey Patteron (Mary-Lousie Parker) and Ida Silver (Holland Taylor) all matter. The fact Bill has five people who like him is a source of grumpy astonishment for him but for us it’s a chance to see the man, and the case that almost broke him, from multiple angles.

Holly, an OCD sufferer played with extraordinary charm by Gibney, sees Bill’s inherent kindness and totally understands his need to Solve The Case. Jerome is a cheerful, highly competent and fundamentally good kid whose goodness terrifies Hodges with how fragile it is and their scenes crackle with snippy paternal concern. Lawrence plays Dixon with incredible calm and self-awareness and quietly gives him a lot of emotional nuance as he moves from humouring his old partner to backing him to the hilt. Parker and Taylor steal the show though, as Bill’s client and occasional lover and his serene neighbour. Parker attacks every scene with a sparky energy that is the perfect counter-balance to Gleeson’s Irish bear, and Taylor is regal as the neighbour who is far more at peace with their age than Bill is and far more attached to him than he cares to admit.

At the core of them all is Gleeson turning in career best work yet again as a man profoundly annoyed at everyone and everything. Bill Hodges isn’t broken but he is every shade of done and Gleeson’s seething, grieving rage is furious, charming, funny and very sad often all at once. The show leans into him too and giving Gleeson the line ‘There’s only so much arse I’ll kiss. I’ve no talent for puckery’ is a public service I thank them for.

Brady’s side of things is just as strongly acted but less successful. A major part of this is the one change the show should have made but didn’t. Kelly Lynch is excellent as Deborah, Brady’s alcoholic, abusive mother. She’s clearly aware she’s a monster but can’t be anything else and Lynch does excellent, uncomfortable work in every scene with Treadaway. The problem isn’t her, or the adaptation but the script. Brady, in the novel, is an evil fat guy and the physical shift by casting Harry Treadaway pays off every time he’s on screen. Treadaway vibrates with wiry rage, and shows us so much of Brady’s mind by showing us how carefully this monster impersonates a real person. Lynch, unfortunately, gets the standard issue King Evil Woman playbook. She does good work with it but she shouldn’t have to.

Harry Treadaway’s constant tension is never less than compelling though and his best scenes are in what amounts to the darkest timeline version of Clerks imaginable. Brady works at an electronics store under Robi (Robert Stanton), a man David Brent would take to one side and tell to calm the Hell down. A legend in his own lunchbreak, Robi is a bitter, snippy monstrosity who alternates between fawning over his employees and chewing them out. His most frequent targets are Brady and Lou (Breeda Wool), Brady’s best friend. Robi’s the living embodiment of the Peter Principle, Brady is a monster wearing a boy suit and Lou is cheerfully out, cheerfully unwilling to deal with any nonsense and increasingly done with Robi’s rank cowardice. I could watch the three of them suffering through a work day for hours and the show cleverly uses the store as a way to explore both the collapse of the town and the different kinds of monsters crawling its streets. A white supremacist client gives Robi a chance to fawn and Brady a chance to flex his homicide muscles while Robi’s ambitions paying off sets up the big finish for him, Lou, Brady and the story. This stuff is uncomfortable but brilliantly acted and written and serves as a clever counterpoint to Hodges’ tetchy, but loving, adoptive family.

These two groups collide and wrap around one another in an escalating series of clashes which, again, never lose sight of the two broken men at the core of the story.

Verdict: It’s a grounded, straightforward story told with consistent intelligence, compassion and horror. Everything, even the credits, serve the story and everything serves the story very well. Bleak, funny, brilliantly acted and essential. I’m diving straight into season 2.

Alasdair Stuart

Mr Mercedes, seasons 1 to 3, are all currently on Disney Plus