Producers: David Haring, James Harris, Mark Lane, Scott Mann and Christian Mercuri   Director: Scott Mann   Screenplay: Jonathan Frank and Scott Mann   Cast:  Grace Caroline Currey, Virginia Gardner, Jeffrey Dean Morgan, Mason Gooding and Jasper Cole   Distributor: Lionsgate

Grade: B-

Scott Mann’s thriller is clearly designed to create high tension, if you’ll pardon the expression, and manages to do so intermittently despite running on a mite too long.

“Fall” is a very simple story.  In a prologue we see happy-go-lucky Becky and Dan Connor (Grace Caroline Currey and Mason Gooding) rock-climbing a steep cliff with their ebullient friend and wannabe YouTube celebrity Shiloh Hunter (Virginia Gardner)  Sadly, things go awry and Dan falls to his death despite Becky’s desperate efforts to save him.

A year later she’s still in a deep depression that her father (Jeffrey Dean Morgan) can’t punch through.  So he enlists Hunter to barge in and insist that Becky do a climb with her to the top of a 2,000-foot abandoned communications tower in the California desert.  Not only will doing so overcome her fear of climbing again, but allow her to come to terms with her grief by releasing Dan’s ashes, which have been collecting dust in a cardboard box in her littered kitchen, from the octagonal ramp near the tower’s top.  (Only a pole, with a blinking red light atop it to warn off aircraft, rises from there.)  Of course, Hunter will also take the opportunity to post plenty of photos and videos of her stunts to satisfy her internet fans.

It’s a risky business, of course, as the no trespassing sign on the fence surrounding the tower warns.  And frankly the pair don’t take many precautions before starting up the rickety, rusty structure.  Loquacious Hunter announces the climb to her 60,000 followers, but doesn’t appear to have enlisted anybody to send help if they don’t hear from her in due course, not realizing that at a certain point they’ll be too high for cell phone reception.

But she has brought some equipment, including not only ropes and cables, her phone and a selfie stick to record her more audacious moves, but food and water and—to top it off—a drone for aerial photography.  At first all goes well, despite Becky’s initial trepidation.  They ascend the ladder inside a cage protecting it for the lower 1,800 feet with relative ease despite some creaking bolts and a couple of rusted-out steps, and even the last two hundred feet above the derelict transmitters, where the ladder is just attached to the outside of the tower, don’t tax them overmuch.  They reach the platform and celebrate their triumph even as Becky sends Dan’s ashes flying into the wind with words of remembrance.

But then disaster strikes.  When they attempt a descent, the outside ladder breaks off and falls, leaving them stranded.  Their phones are useless, of course, except for Becky’s urge to check her photos of Dan.

They’ll use the drone to try to attract attention, but of course its battery quickly runs out, which requires Becky to shimmy up the pole to the blinking link in an attempt to recharge it.  A guy (Jasper Cole) walks by with his dog, but can’t hear their screams.  Becky gets a severe gash on her thigh.  A flare gun at first malfunctions and then fails to bring help.

In other words, Mann and Jonathan Frank resort to virtually every trick in the screenwriter’s playbook to jump-start the suspense whenever it lags.  Unfortunately, they also prolong the last act with some soap-operatic turns as the women share long-buried secrets, and that temporarily saps the energy from the proceedings.  Happily they rouse themselves to deliver a pulse-pounding finale when a vulture the women had observed feasting on a dog’s remains as they approached the tower returns for another potential meal, and last-ditch attempts to reach safety take a desperate turn.

But while the script has its ups and downs in terms of both episodes and dialogue, and the acting is uneven (there are points when both lead performances would have benefited from a bit of restraint), visually the picture is remarkably convincing for such a modestly-budgeted effort.  Mann works with cinematographer MacGregor and the visual effects team to fashion swooping shots that rarely look phony and show us the action from multiple perspectives, and the team of stunt people do yeoman service in maintaining a sense of realism.  And while editor Robert Hall could have been more aggressive in paring away duller material, he skillfully weaves MacGregor’s varied viewpoints into tense montages.  Meanwhile Tim Despic’s score ably adds to the sense of foreboding.

It goes without saying that acrophobics are advised to give “Fall” a pass, but for everyone else it’s a nifty little nail-biter that leaves many of Hollywood’s bloated tentpole action movies in the shade.