A mummy movie is possibly the easiest kind of horror movie to make — it comes to life and terrorizes the living. Simple, but effective.

And yet “The Eternal: Kiss of the Mummy” (aka “Trance”) has managed to screw that simple formula up. Despite the ever-interesting presence of Christopher Walken and some pretty cinematography, the story itself is a flaccid, flabby mess of plot holes and basic writing errors — including some of the least sympathetic characters I’ve ever seen in a movie.

Nora (Alison Elliott) and Jim (Jared Harris) are a pair of wealthy alcoholics in New York, who have decided to dry out on a visit to her grandmother in Ireland. Yes, they plan to dry out in the land of Guinness, because apparently it doesn’t count as booze. But when they arrive, Nora immediately blacks out and crashes the car.

And it keeps getting better — her grandmother has that highly selected senility you only see in movies, and her weird uncle Bill (Walken) only seems interested in the bog-preserved mummy of a druid witch who murder-suicided in the Iron Age. Of course, the mummy comes back to life… for no reason that’s ever explained… and she looks exactly like Nora. Now she apparently wants to steal Nora’s body… even though her own body seems to be working fine.

Director/writer Michael Almereyda seems to have only a vague idea of how proper storytelling works. Important characters appear without introduction two-thirds of the way through, logic is constantly violated (so Niamh doesn’t realize that a cigarette is ON FIRE, but she knows what whiskey is?), and the awkward climax ends up pretty much making no sense at all.

Worst of all: huge oozing lumps of exposition are constantly thrown at us like lumps of excrement… from people who couldn’t POSSIBLY know what they are talking about. How does Bill know the history of Niamh? Magic, apparently. How does Alice know all about her powers and intentions? Never explained. It becomes infuriating after awhile, especially when you realize that Alice is JUST there to exposit.

Almereyda tries to compensate by draping the movie in a dreamy atmosphere and Ireland’s peaty, raw beauty… but it’s not enough. The movie sludges by at a painfully slow pace, with lots of people wandering around and having the world’s slowest conversations, most of which are pretentious muckity-mystical drivel (“Every day; all the time. You wake up, open your eyes, take a breath, start over: that’s how it is”). And of course, Alice monologues over everything. EVERYTHING.

And rarely do you see a movie that is so padded, yet STILL manages to drag by at a snail’s pace. For instance, several characters fall down the stairs. There’s apparently no symbolic meaning to it — they just fall down the stairs because it eats up a few minutes of screen time and looks dramatic.

It also has a cast where you root for nobody, because nobody is likable. Christopher Walken comes the closest merely by being himself — weird, off-kilter, and utterly unconvincing as a lifelong resident of Ireland. But he sadly exits the movie after only a few scenes, and we’re left with… everyone else.

I kept waiting for a moment to come when we start to like and empathize with the lead characters — a pair of rich, irresponsible alcoholics — only to eventually realize that Almereyda intended for us to like them already. Elliott and Harris are mediocre and charmless here, especially since Elliott has to play the dual role of Nora and Niamh, which she does with slack-jawed dullness worthy of Kristen Stewart.

And the character of Alice is the most naked, blatant “exposition fairy” that I have ever seen in a film. I kept thinking that she was the love child that Nora claimed to have aborted, but it turns out that she is nobody special. Just a source of pseudo-mystical narration… and nothing else.

Watching “The Eternal: Kiss of the Mummy” is like being slowly dragged facedown through Ireland’s mud — it will leave you cold and miserable. And eventually, you’ll want a Guinness to dull the pain.