Chon Wang, a Chinese imperial guard, finds himself on a dramatic quest when Princess Pei-Pei, whom he holds dear, is tragically kidnapped and taken to America. Despite his heartfelt determination, Wang is not among the three guards chosen by the Emperor of China to rescue her. However, after admitting that the princess’s abduction was partly his fault, he is sent along, largely as a burden the Emperor hopes the "foreign devils" will eliminate.
His journey leads him to Nevada, where he encounters Roy O'Bannon, an outlaw whose gang hijacks the train Wang is traveling on. When one of Roy's gang members, Wallace, fatally harms Wang's uncle, the imperial guard vows to pursue the outlaws. Armed with only his skills and determination, he ingeniously detaches the train cars to evade capture. Meanwhile, Wallace seizes control from Roy, leaving him helplessly buried in the desert.
While this is unfolding, Princess Pei-Pei, previously led to believe she was escaping an arranged marriage, discovers the grim reality of her abduction by an agent of the infamous Lo Fong, a traitor from the Forbidden City. Upon encountering Roy, who is still trapped in the sand, Chon Wang demands directions to Carson City, tools of survival in hand—two chopsticks—as Roy, with an air of sarcasm, echoes, "The city's on the other side of a mountain."
Crossing paths with a Sioux tribe, Wang heroically saves a boy from the Crow tribe, leading to a reluctant marriage proposal from the chief's daughter, Falling Leaves. After an explosive encounter in a tavern ignites a brawl with Roy, both friends ultimately find themselves behind bars. However, Falling Leaves, driven by loyalty, orchestrates their escape, allowing Roy to teach Wang the art of cowboy life.
Upon reaching Carson City, the duo's escapade takes a menacing turn when they realize they are both targets of Marshal Nathan Van Cleef, allied with Lo Fong. Sought after and cornered in a bordello—Roy's so-called "hideout"—a drunken escapade leads to their capture. It soon comes to light that Lo Fong is the mastermind behind Pei-Pei's kidnapping.
As they await their fate, Wang employs his wits to break free, with Falling Leaves shooting Roy loose just in time for them to evade a deathly hangman's noose. Torn by betrayal after hearing Roy claim he wasn't a friend, Wang rides off alone to find the princess, but their camaraderie soon rekindles when Roy bravely rescues him from Lo Fong.
Their final showdown occurs at the Carson City Mission church, where a ransom exchange spirals into chaos. As the three imperial guards deliver the gold for Pei-Pei's return, loyalties are tested. Amid a fierce melee between the Chinese guards and Lo Fong, Van Cleef confronts Roy in a dramatic shootout. The situation escalates until Wang, confronting Lo Fong in the bell tower, cleverly dismantles the bell, leading to a climactic ending with Lo Fong's demise.
Once the dust settles, the Imperial Guards, now swayed by Wang's resolve, choose to allow Pei-Pei her freedom. Wallace's gang soon storms the mission, calling out for Wang and Roy, but they find an unexpected alliance with the local Natives. At a Chinese cultural celebration, Roy expresses gratitude to Falling Leaves, sealing their bond with a passionate kiss as Wang joyfully grasps Pei-Pei's hand. Finally, the duo emerges as the new sheriffs, galloping off to confront another band of train robbers, their friendship and adventures continuing to flourish.
