Ghost of Mae Nak is an updating of one of the most popular ghost stories in Thailand, which has been the basis for over 20 movies from the silent era to the present. The original story concerns a 19th century rural villager, Mak, who returns home from war not knowing that his wife, Nak, is a now a ghost. She died during childbirth while he was away. When the villagers try to warn Mak that the woman he came home to is a ghost, Nak kills and harasses anybody who threatens to separate the two until Buddhist monks finally exorcise her unnatural spirit. Though Mak and Nak are victims of dire circumstances, the village must exert control in order to keep their tenuous society intact.
The tale is related in this film through the grandmother, suitably wrinkled and foreboding, of a modern-day girl named Nak (Pataratida Pacharawirapong), who is not dead. She is engaged to her own Mak (Siwat Chotchaicharin). After this cute idealistic couple gets married and moves into a decrepit house, the original ghost Nak (Porntip Papanai), now named Mae Nak for clarity, starts haunting Mak to try and get him to save her still-tortured soul. Apparently the Buddhist monks who originally exorcised her cut out a portion of her skull, which Mak unknowingly bought in a shop, and which needs to be placed back in the corpse's head before she can really rest in peace. While they try to figure what it is that Mae Nak wants, the ghost helps Mak and Nak by threatening sleazy city types (a shady real estate dealer, a couple of thieves, a geeky crush who won't take no for answer) taking advantage of their precocious naïveté. After Mak is hit by a car and goes into a coma, it's up to Nak to return the bone and save her marriage. ~ Michael Buening