Well, knock me over and take my movie reviewing license for a year. A good Megan Fox movie? Will wonders never cease?

Just this week, the long-ago flash in the cinematic pan was desperately floating “date Angelina Jolie” suggestions as a way of making herself relevant again. And there are plenty of moments in “Till Death” where the “Transformers” break-out, “Jennifer’s Body” bust reminds us she’s not the best actress sending head-shots around town.

But damn, this lean little thriller works. And she’s not half-bad in it.

Fox plays a wife cheating on her lawyer/husband (Eoin Macken) — and on her anniversary, with a colleague of his (Aml Ameen) no less!

Emma’s told the guy “We can’t do this any more,” and not in the most emotional voice you’ve ever heard. But hubby is giving her hints that he suspects, the way he leaves words hanging in sentences.

“I KNOW…things haven’t been great between us.”

Still, there’s an anniversary dinner, gifts and all. And then “a surprise.” She’s blindfolded as he drives her out into the winter countryside, far away from the city. As we’ve established that Emma met her spouse after being kidnapped — husband Mark had the case file out on his desk — “blindfolded” anything isn’t the most thoughtful surprise.

But they’re going to the lake house — rose petals and candlelight.

A little wine and makeup sex and…she wakes up to a cold house, and a couple of other surprises. He’s handcuffed himself to her. And then he splatters his blood and brains all over her pretty face.

Mark has plotted a murder suicide. He’s hidden her clothes, shoes included. He’s killed the heat in the house. And that’s just a start. She’s trapped and doomed.

After SERIOUSLY under-reacting to the trauma of his suicide and the harrowing nature of her dilemma, Emma tries to shoot the handcuffs off (without first searching him for the key), and realizes there was but one bullet in the revolver.

“I’m gonna cut myself free from you if it’s the LAST thing I do!” only works if there are “sharp objects” there to cut with. Mark has covered all the bases.

And he’s left messages for others, summoning them. Emma is about to confront more people who wish her harm, more obstacles to her survival. NP, she figures.

“I was dragging around your lifeless corpse long BEFORE you put a bullet in that deranged heads of yours!”

Screenwriter Jason Carvey (“New Wave”) and first-time feature director S.K. Dale invent all sorts of details that Mark has seen fit to handle to make escape impossible — a drowned phone, etc.

And then the threat level rises.

Fox has a hard time sustaining the terror her character should feel, or even faking (consistently) the uncontrollable shivers and shakes someone subjected to extreme cold, barefoot and underclothed in the ice and snow would experience. That comes and goes.

But this thriller plays, with realistic real-time problem-solving, melodramatic near-misses, violence and suspense.

We fear for the heroine, even if she’s not nobly heroic, and fret over her strength and cunning even as her resolve never wavers.

Not bad. Not bad at all. Maybe she won’t have to court Jolie after all.

MPA Rating: R for strong violence, grisly images, and language throughout

Cast: Megan Fox, Eoin Macken, Aml Ameen, Callan Mulvey, Jack Roth.

Credits: Directed by S.K. “Scott” Dale, script by Jason Carvey. A Screen Media release.

Running time: 1:28