One can think one has a handle on all every cheese-making nook and cranny of Europe, and then something like “Operation Napoleon” rolls in and makes you realize “Iceland can be cheesy, too!”

“Operation Napoleon” a lumbering B-movie about a lost Nazi transport plane, Americans hellbent on finding it and the plucky, dogged Icelandic loan officer who gets ensnared in their murderous search.

It’s more or less watchable, especially as it takes a turn towards the daffy in the third act. But filmmaker Óskar Thór Axelsson (“I Remember You”) cooks up a classic ninety minute thriller wrapped in an ungainly 110 minute package.

Vivian Ólafsdóttir plays Kristin, the last person you want going over the financials if you haven’t sorted your loan plan properly, crossed all the “t’s” and dotted all the umlauts. She’s pretty much all business, with her brother (Atli Óskar Fjalarsson), a snow-machine rescue patrol member, the only one allowed to prank her.

That’s what she thinks he’s up to when he suddenly goes radio (cell-phone) silent while on Vatnajokull Glacier. But then he hastily dumps video and pictures to her.

Elias and a couple of friends stumbled across a plane in the melting glacier, one with a big’ol Swastika on the tail. It’s a JU-52, and no way is it supposed to be there. They were just poking around in the emerging fuselage when some American “scientists” show up, grinning and gushing about the “climate change” research they’re doing.

Then the “scientist” with the biggest grin (Adesuwa Oni, she played Njinga in Netflix’s “African Queens” series) stabs one of them in the neck with her pencil and Elli’s on the run on his snow machine. SOMEbody wants whatever’s in that plane, and wants to silence anybody else who finds it.

As Kristin has video and images of it, they send an assassin into Reykjavik to get her and her phone. She sees someone murdered and flees into the snowy Icelandic night with neither coat nor shoes nor cops (she “can’t” go to them) for comfort.

She’ll need the help of her boss, a British historian (Jack Fox) she sort of dated and a burly and a goofy Icelandic farmer (Ólafur Darri Ólafsson) to help her survive, get to the bottom of the mystery and free her brother.

But that American military man (Ian Glen, because Brits make the best villainous Americans) is so relentless in his pursuit of her and the contents of aircraft that we know better than to get too attached to any character.

The film, based on a novel by Arnaldur Indriðason, has a whiff of “Smilla’s Sense of Snow” about it, as our mystery “that could change the course of history” is a classic MacGuffin, a plot device that drives the action and yet, in this case, is too pedestrian to ever explain.

Remember that briefcase in “Ronin?” We never found out what was in it, did we? That might have helped this plot, because once things really get cracking in the third act, we’re treated to a lengthy dissertation on what was on the plane, and why it’s worth adding a dead-weight epilogue to a picture that already has pacing problems.

Ólafsdóttir, a bi-lingual (at least) Icelandic actress, makes a very pretty and engaging lead, although the injuries her character sustains make her fight scenes even less believable than the usual model-gorgeous/runway-thin actress throwing haymakers heroine.

The script and direction let Kristin lose track of her objective — that urgent need to save her brother — as she pokes around and dodges death and assumes, all along, that the bad guys haven’t killed him on the spot.

Fox is a bit bland as the bookish love interest. Man-mountain Ólafsson is a walking, joking sight gag. But Glen is as scary as ever as the fanatic hellbent on getting what he wants, even if he has to threaten the U.S. Ambassador and kill a few locals along the way.

The picture’s third act peaks almost make it worth recommending. And then the climax is chased with a corny anti-climax and even that momentary buzz vanishes.

Still, as hot as this summer has been, seeing a bunch of chases and shoot-outs in the Icelandic snow is almost the only definition of “escape” at the movies that matters.

Rating: unrated, violence

Cast: Vivian Ólafsdóttir, Ian Glen, Jack Fox, Atli Óskar Fjalarsson, Adesuwa Oni, Annette Badland and Ólafur Darri Ólafsson

Credits: Directed by Óskar Thór Axelsson, scripted by Marteinn Thorisson, based on a novel Arnaldur Indriðason. A Magnolia release.

Running time: 1:53