20 years ago, M. Night Shyamalan’s best sci-fi thriller delivered his worst twist

While several of M. Night Shyamalan’s signature twists have partly justified all the early Hitchcockian comparisons (The Sixth Sense’s “He was dead all along,” The Visit’s “They’re not the real grandparents,” Unbreakable’s “The mentor is the baddie”), others have suggested he’s more Emperor’s New Clothes than Master of Suspense.

You can almost still hear the mass of groans that reverberated around The Lady in the Water’s damp squib of a reveal (essentially all fairy-tale tropes aren’t real). Glass stuffed not just one but three similarly underwhelming twists into its final minutes (the big masterplan was a viral video??). And The Happening’s cack-handed environmental warning (mass suicides have been caused by pissed-off trees as payback for human damage to the planet) very nearly killed Shyamalan’s career: We’re still not sure how Mark Wahlberg recovered, either, after that deadly serious apology to a plant.

Yet at least these ridiculous explanations were in keeping with what went before. Signs’ big surprise, on the other hand, feels distinctly at odds with its previous 95 minutes, ruining what would otherwise have become Shyamalan’s crowning glory. Following the double whammy of The Sixth Sense and Unbreakable, it was also the first indication the filmmaker was susceptible to the truly illogical.

Celebrating its 20th anniversary this month (Aug. 2), Signs stars Mel Gibson as Graham Hess, a former Episcopal priest already struggling to cope with the loss of both his wife and his faith when his rural Pennsylvania farm comes under attack from a mysterious force. At first, the large crop circles are dismissed by police as the work of two local vandals (or amusingly, female Scandinavian Olympians). However, alongside his fallen baseball star younger brother Merrill (Joaquin Phoenix), well-read asthmatic son Morgan (Rory Culkin), and OCD-afflicted daughter Bo (Abigail Breslin), Graham soon discovers the threat is extraterrestrial.

Whereas Shyamalan went big with his other end-of-the-world tales The Happening and After Earth, here he opts for a more intimate approach, focusing almost entirely on the Hess family and their isolated surroundings. Indeed, Cherry Jones’ kindly cop and the guilt-stricken man who killed Graham’s wife in a car accident (Shyamalan in one of his obligatory cameos) are the only other characters to get more than a few lines.

Luckily, the central four make for interesting company. Gibson, who wouldn’t play the leading man again for another eight years, signs off with one of the most impressively understated performances of his career: the flashback scene in which Graham says goodbye to his dying wife is genuinely gut-punching. It’s also refreshing to see Phoenix, often so overwhelmingly intense, tone it down a little in a turn that could even be described as light comic relief. Watch how he punctures his brother’s existential musings with an anecdote about a vomiting near-miss. And the young Culkin and Breslin show early glimpses of their potential as two kids intrigued and terrified by what’s truly out there.

Shyamalan is in fine form throughout, too, steadily cranking up the tension with several memorable, yet still small-scale set pieces such as an eerie nighttime chase through the cornfields and the initial alien encounter which results in a wince-inducing finger chop. And although the first clear glimpse of the visitors suggests the costume team simply raided the nearest fancy dress shop, its unexpected source — broad daylight camcorder footage from a kids’ birthday party shown on a news bulletin — still sends a chill through the bones.

The anchorwoman’s “what you’re about to see may disturb you” warning could also be applied to the start of the climactic scene as the unwanted guests wage a full-out world war. Again, we only ever see the attack from the Hess’ perspective as they attempt to barricade themselves in the basement. By restricting the presence of the aliens to an array of menacing sounds and the odd hand creeping under the doorway, however, Shyamalan appears to realize the fear of the unknown can be far more effective.

Inevitably, Signs does eventually have to show its monsters off. But while they don’t look any less hastily stitched together in full view, it’s not their aesthetics that ruins things. It’s their Kryptonite. For some baffling reason, this apparently intelligent race has journeyed through space to stage a hostile takeover of a planet whose surface is covered by 71 percent of a substance they have a fatal aversion to. Yes, incredibly, all it takes to end their reign of terror is a simple splash of water.

It’s a ludicrous weakness compounded by the contrived circumstances the film sets up for it to be exposed. The reason Morgan is constantly shown with his inhaler? Well, the closing of his lungs means he doesn’t breathe in the toxic gas unleashed by the alien holding him. Merrill’s past sporting life ensures there’s a conveniently-placed baseball bat just waiting to knock over all the glasses of water (the last words of Graham’s wife were what else but “swing away”). And why are these scattered around the house in the first place? Bo’s obsession with the drinking quality of H2O, obviously.

Of course, as foreshadowed by that serious conversation on the sofa with Merrill, Graham doesn’t see all this as mere coincidence but a “sign” there’s a higher calling with a master plan, albeit one which allowed a human-harvesting alien race to go on the rampage. By the final scene, he’s back in his clerical collar, ready to spread the word once more. Understandably, most viewers, then unused to the director dropping the ball so clumsily, weren’t willing to accept things at such face value.

No doubt Shyamalan was hoping to assert himself as one of cinema’s new great philosophers. The only life lesson he truly taught here, though, was how to snatch defeat from the jaws of victory.