SYNOPSIS:

In Kalasin, Thailand,  a young girl named  Kanok Monapa, wakes after a horrific nightmare and senses a ghost called Phi tai hong presence, looking like her doppelgänger.  Phi tai hong defeats the Phi ban phi ruean, the benevolent spirits that protect houses and the family from bad luck and any invasion of wandering evil spirits.  The two fight, breaking a bamboo chair. Kanok stabs her doppelgänger with a large shard of bambooo from the chair. The body reverts to Sup her secretive father. Sometime later, Achara Bangchang moves to her deceased grandmother Ploy's organic farm with her American husband John Smith. Sup the neighbor who was checking on the farm comes to hand over the keys.  Achara begins experiencing paranormal events in the house including a heavy sleeping paralyze. On the following morning,  John goes to look for firewood and finds a clay pot under a tree and takes it with him home to use as a flower pot.  John insists on using the pot against Achara's will. After making love, Achara who is a back sleeper drifts into sleep while John nods off lying on his face. Another set of paranormal events plague Achara. Achara claims an evil presence is haunting her grandmother's house that's why she was attacked by phǐǐ am. John discarded the idea of supernaturals. Later they are invited to dinner by Sup who is happy because his daughter Kanok is discharged from a psychiatric institution after seven months.  Sup claims that the spirit haunting Achara's grandmother's house must be Ploy because she had committed suicide and advised Achara to light the sage. As Achara wafts the smoke of sage into the corners of the room she sees a rose being plucked off from the pot by something invisible through the window.  Frightened Achara rushes to wake up John to see him in the middle of a terrible fight with a night hag where he sees a woman similar to the one he had seen in a photo in Sup's house pressing him down to take off his life, and is saved by Achara. In the morning Achara found the rose still in the flower pot. John learns that the woman Pimchan, in the photo is Sup's wife who disappeared some years ago. Psychic Dr. Badin visits Achara and John. He determines there is a poltergeist intrusion involving several ghosts, whose families must engage in a variety of rituals and offerings to guide the suffering spirit into its next life or they must be disposed of by Mo phi.  He warns them not to sleep on their back because back sleepers resemble dead people. He advises not to communicate with the ghost without Mo phi. After Dr.  Badin left, Chaiya and Dara, Achara's cousin paid an unexpected visit. Chaiya and Dara learn about the ghosts and try to chase them out provoking the spirits, making them angrier and turning them into a poltergeist, starting with minor noises, flickering lights, and bedroom door movements. These phenomena initially seem benign, but soon grow sinister. They escalate into loud thuds, violent door slamming, and demonic grunts and screeches.  A TV set breaks, silverware bends, and furniture moves on its own. The roof opens and  Chaiya begins to be pulled up with a strong wind. John and Achara rescue Chaiya. Chaiya and Dara rush outside to leave that night and Achara pleads with John to join them but John abruptly insists on staying. After  Chaiya and Dara's departure, everything comes to calm.  Achara and John sleep peacefully. Dara and Chaiya wander the whole night driving around but getting nowhere till they knock on Kanon's doppelgänger. The following morning, Chaiya and Dara find themselves sitting on the couch in the sitting room and dawns on them that their night drive was a hallucination. Chaya and Dara leave to contact Chaya's uncle a blind Mo phi well known for seeing spirit things. Kanok starts to gain her memory and remembers what happened on the day she stabbed her father.  Kanok was struggling to celebrate her 12th  birthday. Kanok had gone through her mother's old belongings and found a photo album that showed a photo of identical conjoined twins,  and another photo that showed that the twins had been successfully separated written some names on the back 'Kanok and  Kanokwan'. That night she slept with the photos under her pillow.  Kanok becomes convinced that her nightmares are messages from her twin sister, trying to tell her something.  Kanok confronts her father who admits that Kanok and Kanokwan are conjoined twins and Kwanokwan dies a few months after a successful surgery to separate them. Her mother Pimchan could not cope with the situation and she left the farm. Kanok starts to hear voices telling her to kill her father but She overcomes them and runs away. Chaiya and Dara arrive with Mo phi. Mo phi determines the unrest spirits, Phi tai thang klom a ghost of a woman who was killed during childbirth with the baby still inside her, and two Phi Tai Hong, a ghost of a murdered man and woman. He says all the spirits have been buried on the farm.  It is revealed that the spirit of the murdered woman is Achara's grandmother, she didn't commit suicide.  The spirit of a murdered man is Dr.  Anuman and the spirit of a pregnant woman is Kanon's mother. Mo phi  conducts a ritual and confines the spirits to an earthen jar, which he seals so that he may go and throw it into a deep canal, river or lake. Mo phi proclaims the house is "clean". However, he detects a dark present he calls "Dust", who is preventing another spirit from crossing over. He asks John to bring the clay pot he found in the forest.  Suddenly Kanok rushes in, and Dara mistakes her for the ghost they run over in their hallucination. Dara picks up the pot and hurls it at Kanok who catches it. Kanok is possessed and speaks in Kanokwan's voice. It is finally revealed that after Kanok and Kanokwan were finally separated kanokwan was permanently disabled, and Kanok developed a heart problem. Their parents decide to kill Kanokwan and give her heart to Kanok. Kanokwan's spirit becomes vengeful and demonic. Kanokwan made Kanon kill her mother during her labor. She also made Kanon kill Dr. Anuman who performed the heart plants on her. All the bodies were disposed of by her father on their neighbor's farm. Ploy catches Sup red-handed burying the body of Dr.  Anuman and Sup strangles her to death and makes it look as if she has committed suicide.  With the help of voodoo, Sup made a pot with the clay from the grave where they had buried Kanokwan to confine her spirit and dumped the pot in the forest. Kanokwan's spirit was now freed with John. The possessed Kanok tries to kill everyone in the house until Mo phi throws black water on her. John, Mophi and Chaiya take the clay pot to Kanokwan's grave leaving Achara and Dara to take care of Kanok who has fainted. Mo phi breaks the clay pot putting a curse "dust to dust".  There is a whirlwind that blows the dust about in the air, and then a reincarnated Kanokwan appears. At Kanok's house, Sup opens the door to welcome Kanok only to be strangled to death by Kanokwan's ghost.