By Jaysus, is Wild Mountain Thyme a great piece of shite. Sure, and never did I see a film about Ireland and the Irish that was so desperately addicted to the most revolting cartoon stereotypes - in comparison The Quiet Man looks like a documentary, Waking Ned looks like guttural neorealism, and that episode of Star Trek: The Next Generation about the filthy space Irish who try to light a fire in the Enterprise cargo bay to cook food and heat their still is... well, faith and begorrah, sure it's not worse than this, anyway.

The film is the brainchild of writer-director John Patrick Shanley, adapting his own 2014 play Outsider Mullingar, which in turn appears to have been adapted from a Lucky Charms commercial. To its credit, Wild Mountain Thyme lets us know extremely early where to calibrate our expectations, starting with a bit of voiceover narrated by no less Hibernian a personage than Christopher Walken, whose extremely distinctive voice, with its nasal singsong and angular Queens lift, surely ranks him near the bottom of some theoretical list of actors that I'd like to hear tackle an Irish brogue. The results are no better than my deepest fears, resulting in some hideous cartoon abomination that marries the garrulous warmth of a Barry Fitzgerald with the clammy chill of a skeletal gravedigger. It sounds not like the accent of a talkative old Irishman, but a soulless murderbot weakly feigning human charisma in a attempt to put us at ease. That 2020 would have find it within its wretchedness to produce an even worse Irish accent than the one that Judi Dench snarled out in Artemis Fowl comes as a surprise so great that it's almost exciting.

The film's accent game is, in general, heart-stoppingly bad: of the three leads other than Walken, Emily Blunt and Jamie Dornan are at least from the British Isles, and so at least get close to something human, though I am not willing to say that they get all that close to an Irish human (and Dornan is even from Ireland! But Northern Ireland, the wrong part). Jon Hamm, the lucky bastard, plays the standard-issue American cousin, so he just gets to talk like Jon Hamm. Anyway, the clattering of choked accents makes the whole move feel genuinely surreal, all the more so when Blunt and Dornan get locked into conversations that have been swiftly paced and cut to turn their banter into little rocket-powered verbal battles, and the clipped rhythms, mixed with the gaudy accents, make it all too stunningly garish for words.

But I would hate to get so hung up on accents that I lost sight of what else is bad about that opening line, in which McWalken does two things: first, introduces himself as Tony Reilly, and second, he lets us know that he is presently dead, and the story will mostly take place before he died. So boom, just like that, we get to find out that it's a stubbornly twee character drama we're in for, one that is to be absolutely mired in vaguely magical-realist clichés. That will pay off in spades to kick off the last act, but before we get to that point, let us briefly consider the story Shanley has cobbled together out of generations of dumb light drama about colorfully rural Irish types: Tony is a landowner, and his son Anthony (Dornan) would ordinarily be set up to receive the land as an inheritance, but there's just something... off about Anthony. There is, to be sure, something off about most of the people around these parts; it is the kind of film that takes it as given that Irish people are quirky, and the quirkier, the more Irish. And so it gives everybody in the film, not so much a personality, as an attitude, one that's some combination of Irish-ready adjectives like "stubborn" and "traditional" and "redheaded".

Anyway Tony doesn't really want to give Anthony the land, but he does have an American nephew, Adam (Hamm), and he hopes to leave the land to him. This is a scandal to everyone who hears it, most of all to the Reillys' neighbor, Rosemary Muldoon (Blunt) - Rosemary! In a film with "thyme" in the title! Ain't that a stinker! - who openly and madly loves Anthony, though if he notices this, he hasn't done anything about it. She's a bit off herself, of course, in addition to having the fiery impatience and irascibility that are the genetic predispositions of redheads, and has been ever since her dad, a fixture in the community, died and left her in charge of the whole farm. But she's smart and capable, and not at all interested in whatever Yank fuckery Adam is bringing with him. Naturally, this sets up a love triangle, and Shanley does try with all his might to make us believe that it might have some legs to it, despite Rosemary's overt disinterest in Adam and Blunt and Hamm's perfect lack of chemistry.

To this romantic melodrama that can't rouse itself awake - and it makes up the clear majority of the film's narrative, so that's a fun thing to wade through - Shanley adds the grotesquely over-literal, graceless directorial style that has now marked two-thirds of his very peculiar directorial career, which started in 1990 with the sly, sardonic comedy Joe Versus the Volcano. In the intervening 30 years, he's only made one other movie, the 2008 adaptation of his stageplay Doubt, which is where he first demonstrated all of the terrible instincts that have now torpedoed Wild Mountain Thyme. Shanley is a hilariously dour film director, electing to create a mood of looming foreboding at the expense of all else, sucking all the air out of his films like a decompression failure in a high-altitude jet. It's a crazily heavy-handed style that very nearly ruined Doubt, a terrifically watchable play that should be more or less unruinable with an even vaguely adequate cast; Outside Mullingar, which is a stupidly unimaginative pack of stereotypes, had no prayer. And thus it is that the film feels oppressive, even as Stephen Goldblatt's cinematography works hard to breath vivid greens and striking overcast greys into the fields of Ireland, quite possible the most impossible landscape on the surface of the planet to make ugly. And so it is that Wild Mountain Thyme is at least beautiful, but it is a suffocating beauty, looming with pregnant menace. Dramatic thunderclaps punctuate lines of dialogue multiple times, and not once is it apparent that we are meant to find that funny.

So a pretty hideously boring, wearying melodrama that probably qualifies as a hate crime against the Irish. But then, there is The Twist, which is the only thing that anybody knows about; either they know what The Twist is, and are stunned into deadened shock, or they know that there is The Twist, but it has been cautiously hidden. First a point of order: it is not a Twist. It is a Reveal, and only barely. Twists redefine what we've seen and cause us to realise that what we thought was so isn't, and our relationship to the film changes. Reveals provide pertinent hidden information. What happens around the three-quarter mark of Wild Mountain Thyme barely even feels like a complication; it adds a long scene of Blunt and Dornan talking their unendurably brittle, machine-like "banter", and somehow manages to resolve itself without any trouble at all. This is, to be clear, part of what makes it so damned mindblowing. Because The Reveal is fucking crazy, perfectly pitched to make sure that if you have been drifting from boredom or annoyance, or most likely a bubbling combination of the two, you will immediately snap back to focus with minutest attention on what's going on, if only to make sure you actually just heard that (the film obligingly repeats itself, to give us an assurance that yes, we sure did). It doesn't come from nowhere, but it's the next-closest place to nowhere, and it is so bizarrely out of kilter with anything we might have suspected would be an option for this narrative universe that it feels like it should fundamentally switch not just the tone, but the the entire genre.

And it just lies there and then goes away. After having dropped a nuclear bomb on his script, Shanley treats it with the urgency of a disagreement over whether or not there's enough salt in the mashed potatoes. This is what makes The Reveal so dumbfounding: not just that is profoundly inexplicable and destructive, but that it is inexplicable and destructive and he doesn't even do anything with it. That takes some unerringly bad instincts as a writer, and this from a man with an Oscar, a Tony, a Drama Desk Award, and a Pulitzer. The spectacle of watching just how much misguided confidence one man can place in his own writing is easily the foremost  reason to see Wild Mountain Thyme, unless the idea of Blunt studiously singing her way through the titular folk song without her breaking gaudy accent sounds appealing to you. There's no sense in which this film is so bad that it's good - it's just bad, in a sullen and soggy way - but it's such a baffling, singular object that I can't help but want to urge every last one of you to see it just for the sheer "why would you do any of this?" of it all.