No one really goes into "Non-Stop" expecting a grounded, Paul Greengrass-esque procedural. After all, the trailer climaxes with an action beat showing the only thing a Liam Neeson movie character loves more than murdering Albanians in the "Taken" franchise is murdering the laws of physics. No, a viewer buys a ticket and grabs a seat in "Non-Stop" in the hopes of being suckered into ignoring the rules of reality, going along for the ride and having some thrilling nonsense B-movie mystery fun.

In fact, the last time Liam Neeson and director Jaume Collet-Serra teamed up was for "Unknown," a mostly implausible amnesia thriller from 2011. It was ridiculous, but it was impeccably polished ridiculousness, featuring a remarkably deep cast, chilly direction and a tense, intriguing central mystery pulled straight from Hitchcock. Sure, it fell apart afterward, but during the movie, I bought into it and had a good time.

Unfortunately, I could never buy into "Non-Stop." The mystery sets its preposterousness at a dangerously high altitude to begin with, and from there, it only goes up, further and further away from any grounding until it’s bumping up against space, literally defying gravity.

The story – from the rookie trio of John W. Richardson , Chris Roach and Ryan Engle – does have promise. It’s yet another Hitchcock-ian "wrong man mystery" with Neeson playing less Charles Bronson and more Jimmy Stewart. Here he’s Bill Marks, an Irish ex-cop turned alcoholic U.S. air marshal with a tattered family. After getting through security, he boards his next mission – a transatlantic flight from New York to London – all the while ominously eyeing up his fellow passengers.

What should be a simple flight hits turbulence when Marks starts receiving threatening text messages on his private cell line. The stranger demands $150 million be transferred to a bank account or a passenger dies every 20 minutes. When the mystery hijacker comes through on his/her promise of a dead passenger, the hunt begins.

It could be Julianne Moore as Marks’ friendly and inquisitive seat neighbor (a bit suspiciously inquisitive though ...), or perhaps Michelle Dockery from "Downton Abbey" as a helpful flight attendant (maybe too helpful?). She’s making eyes at the co-pilot (Jason Butler Harner), however; maybe they’re in on it together? And what about Scoot McNairy ("Killing Them Softly," "Argo"), who originally said he was on a different flight? Or Lupita Nyong’o? She only has about five lines in the whole movie, but she’s playing a Brit, and as that Super Bowl ad said, British people are generally evil.

Marks starts barking orders and roughing his way through the aisles, interrogating (i.e. punching) every possible suspect and violating civil liberties left and right. Meanwhile, the harried passengers begin to suspect their supposed protector, running frazzled back and forth through the plane with demands, is perhaps behind it all.

Like Neeson and Collet-Serra’s previous collaboration, the overqualified cast is certainly present, playing their various trope-y red herrings with some character, and so is Collet-Serra’s smart and shadowy direction, ably moving the camera around the premise’s confined, highly pressurized space.

The mystery is where things quickly and tragically fall apart for "Non-Stop." Even before the first death, the story demands so much of the audience's suspension of disbelief. The villain's plot is lunacy, the kind of plan that requires an insane level of psychological insight into complete strangers’ behavior plus impeccable future knowledge that one would expect from a clairvoyant or a deity. As the movie goes on – and as the implausibilities pile up – the story’s web of intrigue quickly unravels into a pile of nonsense.

Despite the seemingly loaded set-up (murder mayhem at 45,000 feet!) and the clear craftsmanship on display from Collet-Serra and his cinematographer Flavio Labiano, there’s surprisingly little tension to distract from the plot’s contrivances and glaring silliness. It’s a lot of reading Liam Neeson’s text messages that pop up on screen, which is not as interesting as it sounds.

Meanwhile, Marks frustratingly makes the situation worse with every decision, whether he’s withholding information from his increasingly aggravated fellow passengers or running around the plane violently smashing anyone who looks vaguely sinister. He’s somehow extremely capable and extremely incompetent at the same time.

Eventually, I began to wonder if Neeson’s brute behavior and annoyingly inept decisions were leading up to "Non-Stop" trying to say something about the price and ethics of security. The end reveal, however, muddles up the politics, including a borderline tasteless 9/11 namedrop.

That’s not the only thing the final twist mucks up. Up until that point, "Non-Stop" is senseless but at least fairly diverting and efficiently made. The big reveal, however, makes everything positive from before feel like a cheat. Instead of the clues building up to a suspect, it feels like the scriptwriters suddenly realized they had to start bringing this thing to a close and picked a culprit at random. What should be the big climax is instead unsatisfying, even more so when the ill thought-out reasoning for the whole elaborate plan is revealed.

A disappointing final twist deserves a disappointing final action sequence as well, choppily edited together and including a critical overload of silliness. There’s a bomb, a shootout, fighter jets in dangerous pursuit and the heroic rescue of an adorable little girl that would rip the limbs off of a lesser man.

It’s the farcical "Taken 2"-esque action finale that the story’s farcical "Taken 2"-esque logic deserves, and by that time, I’d well had my fill of ridiculousness.

If there was a scene where Liam Neeson dragged a lifeless Captain Kareem Abdul-Jabbar past distracted passengers and a blow-up autopilot took over the craft’s reins, I probably wouldn’t have blinked. I probably would’ve had more fun though.