Every 60 years, a swarm of carnivorous, four-legged monsters descend on Northern China to punish its people for their past sins of greed. The Nameless Order were formed to protect the capital city from this hoard of demons, and they erected the Great Wall as their outpost of defense. The Wall is outfitted with technologically advanced (well, for Ancient China) machines of war, and guarded by a devoted army. Meanwhile, a band of Western mercenaries, led by William (Matt Damon) and his partner Pero (Pedro Pascal), are drawn to the Great Wall by rumors that the Order have invented a destructive new weapon: gunpowder. The mercenaries are soon captured and jailed by the Chinese forces, just as the monsters (referred to as the Tao Tei) begin their assault.

Lin Mae (Jing Tian) becomes the Order’s commanding general after tragedy strikes, and she fears that the Tao Tei have evolved and outsmarted the Wall’s defenses. William, an expert marksman, becomes an integral part of the Order’s regrouping efforts, while his pal Pero plots to escape and steal a cache of gunpowder with another jailed Westerner (a sleepwalking Willem Dafoe). As the Tao Tei’s attacks become more effective and the Wall is breached, Mae and her lieutenants are forced to improvise in order to save civilization.

Filmmaker Zhang Yimou certainly has a flare for opulence: After a modest beginning making art-house movies in China, The House of Flying Daggers director helmed the breathtaking opening and closing ceremonies of the 2008 Beijing Summer Olympics. Some of the visuals in The Great Wall are tremendous—the color-coordinated ranks of the Nameless Order and the meticulously choreographed inner workings of the Wall come to mind—but its combat scenes and attempts at emotion are boring, clichéd, or just plain silly.

“Silly” is probably how most viewers walking out of this flick will describe it. Even apart from the nonsensicality of the monsters (which are distractingly CGI’d) and their vague insertion into the backstory, The Great Wall is consistently hobbled by its own script. The story’s main conceit and self-seriousness demand a lot of investment from the audience, but the movie is undermined by the constant, out-of-place one-liners. Just as Damon tried to keep the proceedings light in The Martian, he delivers plenty of deadpan groaners here over the course of a routine Hero’s Journey. The largely Chinese cast are mostly relegated to the sidelines, and have little to do besides echo those tired virtues of honor, courage, and trust.

Regardless of The Great Wall’s complete lack of juice, the clout of its director and stars will make it a global cash cow—and perhaps a harbinger of limp blockbusters to come via the heavily bankrolled Hollywood-to-China pipeline. It’s hard not to be cynical about this film when the motivations of everyone involved appear to be the potential dollar signs rather than any artistic aspirations.