Koo Chi-Ming (Alan Tam) is a life-insurance investigator who while driving on a rainy night to his engagement party, loses control of his car and almost runs over a young girl called Siu-Yu (Ni Shu Chun). Eventually Koo Chi-Ming arrives at his parent's house where the party is being held. He and his father (Bill Tung) soon begin getting henpecked by Koo Chi-Ming's mother (Tang Pik-wan) and his fiancée Ivy (Cecilia Yip). Later on, when the party dies down, everyone decides to have some fun fooling around with a Ouija board by attempting to talk to a spirit. This is commonly known as 玩碟仙 or 'playing with spirits via a saucer'. Before they begin Koo Chi-Ming's little brother explains that after they are finished they must send the spirit back, otherwise a spot of blood will appear under the small saucer they are using and the person last holding the saucer will be haunted by the spirit. At the same time, the young girl Siu Yu who Koo Chi-Ming nearly ran over is at her apartment on the roof with her 4 year old goddaughter Mimi. Siu-Yu sees that Mimi is playing very close to the edge and rushes forward to grab her. Siu-Yu's foot accidentally lands on a skateboard which sends her over the edge of the roof falling to her death. Back at the house, as soon as Siu-Yu dies, the saucer begins to show signs of movement and points out the spirit's name, Chang Siu-Yu and her address. The saucer then begins to circle violently around the board and everyone is thrown backwards, apart from Koo Chi-Ming, who held on until the last movement at which point the saucer flips over to reveal a small spot of blood.
The next day at work, Koo Chi-Ming is handed two cases to investigate by his boss (Philip Chan), one of which belongs to a girl who fell from the roof of a apartment building. Koo takes the other one, but the spirit of Siu-Yu, switched the files. While looking through the case file, Koo Chi-Ming notices that the name and address of the deceased, is the same as the one spelled out on the Ouija board. After visiting the deceased girl's apartment, realizes that the girl who died; Siu-Yu was the girl he almost ran over the night before. Ming is unsure whether or not it was suicide so returns home. All of a sudden the ghost of Siu-Yu appears in front of Ming and tells him that it was a suicide and to pay as the money is for her goddaughter Mimi.
Back at work, Koo Chi-Ming is about to write up his report but his boss intervenes and tells him they can't afford to payout, and to say that the girl committed suicide. Later, Siu-Yu reappears to Ming and he tells her that he can't help as it is his boss's decision. At the recording studio, Siu-Yu begins playing tricks on Koo Chi-Ming's boss and makes a fool out of him on TV, which prompts him to sign the case off as accidental death. Because of this, he blames Koo Chi-Ming and fires him from the company. Koo Chi-Ming takes losing his job hard and decides to get drunk which results in him getting mugged and being thrown in jail. At the police station his old boss appears, posts bail for him and even gives him back his old job with a promotion. When asked why, he tells him that the ghost of Siu-Yu began haunting him and wouldn't leave him alone until he helped.
Now a free man and with a promotion, Ming begins a romantic relationship with Siu-Yu. Eventually Ming's girlfriend, Ivy, finds out that he has fallen in love with a ghost and along with Ming's mother hire the skills of a exorcist called Dr. Han to get rid of the ghost. They go to Koo Chi-Ming's apartment where Dr Han explains that while he is performing the exorcism the front door which he calls 'the door of life' can't be opened as this will cause the 'door of death' to open. He also instructs Ivy to keep Koo Chi-Ming away from his apartment as he tries to exorcise the ghost. So Ivy decides to take Koo Chi-Ming out to a club to distract him, while sitting in a crowd watching a dance performance he spots Siu-Yu on stage and in great distress. At the same time in Koo Chi-Ming's apartment Dr. Han starts to summon Siu-Yu which causes Siu-Yu to disappear in front of Koo Chi-Ming. Leaving Ivy in the club, Ming rushes home as fast as he can in his car to find Dr. Han in the middle of the exorcism. Ming rushes to help Siu-Yu, but by opening the door he triggered the opening of the 'door of death' which at this point Dr. Han as ran away. Everything in the room begins being sucked out the window along with Koo Chi-Ming and Siu-Yu. Koo Chi-Ming grabs hold of the balcony railing but Siu-Yu lets go of his hand and is sucked into the sky. Deeply in love with her Koo Chi-Ming tries to follow her by letting go of the railing but falls 18 floors onto a parked car. After recovering in the hospital, Chi-Ming returns to where he first saw Siu-Yu in hope of finding her. He walks out onto the road and is nearly hit by a car. Looking through the window for a split second, he thought the female driver was Siu-Yu, but then notices it isn't and lets her drive away. With an emotional look, he takes of his glasses, and looks up into the sky with a smile.
Alan Tam as Koo Chi-Ming (古志明) - a insurance investigator who falls in love with a female ghost
Ni Shu Chun as Chang Siu-Yu (張小瑜) - a girl who accidentally died, became a ghost and begins to haunt Chi-Ming
Cecilia Yip as Ivy - Chi-Ming's controlling girlfriend who bosses him around
Tang Pik-wan as Chi-Ming's Mother
Bill Tung as Chi-Ming's Father
Cheng Mang-Ha as Mimi's Grandmother
Tien Feng as Dr. Han - a Taoist priest who tries to exorcise the ghost Siu-Yu