Whisky-sozzled air marshal Bill Marks (Liam Neeson) has to sober up quickly when a text-fiend threatens to kill a passenger every 20 minutes during a transatlantic flight unless he/she gets $150m. With the help of a fellow traveller (Julianne Moore) and a resourceful air hostess (Downton Abbey's Michelle Dockery), Marks attempts to identify the blackmailer... but winds up becoming the chief suspect. Knuckle-biting action at 40,000ft from director Jaume Collet-Serra (Unknown, Orphan).
He plays Bill Marks, a veteran US Air Marshal who has to slurp a shot of whisky in the airport car park before he can summon the drive to do his duty aboard the next flight.
Grumpy and slightly sozzled he may be, but that doesn't stop him quietly clocking his fellow passengers as they're about to board a plane from New York to London.
As the jet gains height everything seems normal...until Bill receives a text telling him that someone on the plane will die every 20 minutes unless $150m is paid into a named account.
Desperate not to alarm the flight, he quietly recruits trustworthy traveller Jen Summers (Moore) and air hostess Nancy (Dockery) to systematically check which passengers are on their phones while he's receiving more messages from the airborne extortionist.
They quickly identify a second air marshal (Anson Mount) acting suspiciously and - following a vicious hand-to-hand ruck in the jet's cramped toilet - Bill breaks his neck when the bounder tries to shoot him. Then he gets another text.
Spanish director Jaume Collet-Serra, who showed he's capable of good things with Unknown (with Neeson) and particularly Orphan, keeps the tension tightly ratcheted, skilfully manipulating subsequent events to suggest that Bill is the bad guy.
A stern-jawed Neeson plays it completely straight, a decision that grows increasingly essential when the narrative threatens to unravel when we learn who is actually behind the high-flying plot.
Collet-Serra builds up a nicely claustrophobic atmosphere as the action unfolds in the oppressive confines of the cabin and there's a rich gallery of supporting characters from a bellicose NYPD officer to an upright British doctor whose Arab appearance provokes plenty of premature speculation.
It's a slickly-made thrill ride that zips along at the speed of a Boeing 767 even if it hits the odd patch of turbulence before touch-down.