In the climax of The Whole Truth, the dark secrets of the family are finally laid bare. It is revealed that Wan, the grandmother, was responsible for poisoning Pinya and Putt, motivated by her disgust for deformities in the family. Wan's hatred for Pinya was rooted in her physical deformities, which led her to poison her with milk, and she continued her hatred towards Putt in a similar way, believing he shared the same flaws. The visions of Pinya—the girl with the hole in her head—were manifestations of Wan's guilt and her suppressed memories, which the children could see because of the alternate reality or wormhole they believed existed. Wan’s denial and the children’s discoveries exposed her true actions, including her deception about Pinya’s death and her attempt to poison her own grandchildren.
Further revelations unravel the tragic truth about the accident involving Mai, the mother, who initially seemed to be in a coma due to an unspecified injury. It turns out Mai was not responsible for the car crash that injured her. Instead, it was Chaiyut, the man initially believed to have caused the accident, who was actually not driving when the incident occurred, and he was manipulated into believing he was at fault. Mr. Somphong, the grandfather, had killed Chaiyut to hide the truth because Chaiyut was the son of a powerful person and might have escaped punishment. This act was part of a broader effort to conceal the family's secrets and maintain their reputation.
The most shocking twist is that Mai herself was responsible for Krit's death. While the official story framed Krit’s death as a suicide, it is revealed that Mai shot Krit out of anger after learning Pinya had died due to her negligence. The bullet in the wall, previously thought to be a suicide note or an accidental gunshot, is actually the bullet Mai fired in her confrontation with Krit. The film concludes with the blurred lines between reality and hallucination, as Mr. Somphong, haunted by hallucinations of the characters involved, ultimately kills what he perceives to be Chaiyut but then realizes it is Wan, who has been shot. Overwhelmed by guilt and madness, his hallucinations and trauma become too much to bear.
In the end, The Whole Truth leaves viewers with a sense of the dark, buried secrets that the family tried to conceal, showing that beneath the surface, their twisted truths and guilt have led to an inevitable, tragic climax. The film suggests that uncovering the full truth often comes at a great personal cost, and the characters are haunted by what they have hidden or denied for so long.
