Cheung Sap-yat Kent Cheng Jak-Si is an exorcist based in Jiangxi, China, who guards a Ming dynasty vase that harbors a demon spirit — a renegade disciple of his own ancestral line. When Cheung’s son Siu-bo leads a faction of Cultural Revolution supporters to seize the vase, Cheung decides to discard it by tossing it into the sea. The vessel drifts across the water and eventually lands in Hong Kong, where it becomes part of a charity auction. The vase is sold for HK$1.8 million to Councillor Steven Kay Stanley Fung Shui-Fan and his son Jacky Jacky Cheung, who bring the mysterious item home with them.
At the Kei mansion, Steven Kay’s devout mother Hung Mei senses something off about the vase, while Steven’s girlfriend Mabel Anglie Leung urges him to take the vase to Chan Pak-tung [Natalis Chan Pak-Cheung], a fortune teller who is secretly Mabel’s lover and part of a scheme to swindle money from Steven. Chan pretends to conduct a Taoist ritual, but his real intent is far from pious. He carelessly scatters cigar ashes into the vase, provoking a first ominous twitch from the demon’s hand that emerges from the porcelain. Chan is knocked aside by a supernatural force and returns the vase to Steven, unaware of the danger he has just invited.
Back at the Kei residence, the vase begins to smoke and the demon fully emerges, striking at Steven and throwing him into unconsciousness. In the meantime, Jacky—who has been playfully scaring his girlfriend Cat Elsie Chan Yik-Si with monster masks—finds himself in a scenario he never expected: a terrifying confrontation with the otherworldly force. The demon, initially repelled by a shrine’s glow, soon possesses Steven, escalated by the chaos surrounding the household. Cheung witnesses the danger and makes a dramatic entrance into Hong Kong after illegally crossing the border, using his supernatural abilities to elude a pursuing police presence and to reach the Kei mansion. He attempts to exorcise the demon, but the possessed Steven thwarts him with a sniper shot, forcing Cheung to retreat.
A tense sequence follows in which Jacky accidentally runs over Cheung with a car, bringing him to Jacky’s home under duress. The doctor is summoned, but Cheung’s tools doom him to be left behind in Jacky’s car, complicating any immediate exorcism. The demon, meanwhile, continues to switch hosts, possessing Stephen at one point and later moving to Cat, creating a mounting sense of peril for everyone involved. The group grows increasingly unsettled as Chan and Cheung try to explain the danger, only to be dismissed by the Kei family, who refuse to acknowledge an actual possession.
As the terror escalates, the demon’s influence extends to Micky (Jacky’s younger sister), who becomes a crucial target. Cheung and Chan realize that only a spiritual pole hidden in the crashed car and a Taoist mirror inside the vase can drive the demon back. They also understand they must summon Cheung’s spirit to aid in the exorcism, even if Cheung’s presence risks more danger for those involved. Jacky and Cat locate the pole in the vehicle pound, while Steven and Chan search for the vase’s mirror, only for the demon to abandon Stephen long enough to possess Micky. In the hospital, Micky’s brainwave activity appears unusually strong, and the demon uses this moment to kill a nurse and threaten others as the chaos unfolds.
With the stakes higher than ever, Cheung explains to Jacky, Stephen, Cat, and Chan that the only path to banishing the demon lies in a carefully staged exorcism: summon Cheung’s spirit by possessing Cat, then have Cheung temporarily inhabit Jacky’s body to confront the demon directly. A fatal obstacle appears when a hospital doctor and nurse discover Cheung’s body and prepare to dissect it, forcing Cheung to reclaim his own form and continue the fight. The trio—Jacky, Cat, and Chan—manage to fend off the demon long enough for Cheung to return and complete the exorcism. The decisive moment arrives when Jacky wields the pole and, despite the risk to his own father’s life, reluctantly drives a fatal blow to vanquish the demon.
In the immediate aftermath, a tree crashes down, seemingly removing the last of Stephen’s possession. Micky reveals a valuable vase delivered to him on the day he began the ordeal, and, exhausted by the trials, Stephen tosses it aside, while Jacky and Cat leap to catch the priceless relic, saving it from shattering as the danger finally subsides. The haunting events leave a lasting impression on all involved, with the vase’s power having been both the source of terror and the catalyst for the unlikely alliance that saved the day.
