A nine-year-old boy, Qingyu's mother Meifeng is arrested for the murder of her husband (Qingyu's stepfather). The pathologist, Chongzhe, who is involved in the case gradually befriends the young boy who is the sole witness in the murder case. He realizes that Qingyu yearns for his paternal father who has mysteriously left them years ago. As Qingyu gets to know Chongzhe better, he starts to explain what he had seen on the night of the accident, causing insufficient evidence to convict Meifeng, and she is released on bail. Later, the body of Qingyu's paternal father is found. Meifeng is immediately arrested again... 被法醫發現驚惶失惜呆坐在一棵巍然樹上的小男孩頓時成了一宗謀殺案的唯一目擊證人. 雖然警方的調查一再顯示小男孩的母親嫌疑最大, 但法醫卻深信幕後黑手是一股強大的超自然力量, 尤其當他發覺小男孩與大樹間似乎存在著一段異乎尋常的親密關係......
