SPOILER ALERT: the following article contains massive spoilers, including the ending. If you have not yet seen the movie, proceed at your own risk, or better, come back to this article later!
Joy is the new maid of a royal house, whose previous maid disappeared under mysterious circumstances and is now haunting and terrorizing the family. Joy works to uncover the reason behind the former maid’s disappearance.
SPOILERS AHEAD
The Maid Plot Summary and Synopsis
Joy (Ploy Sornarin) is hired as a housemaid by a wealthy family consisting of Uma (Savika Chaiyadej), Nirach (Theerapat Sajakul), and their only child and daughter, Nid (Keetapat Pongrue). Mrs. Wan (Natanee Sitthisaman), the head housemaid, reminds Joy not to pry into the affairs of their employers.
Joy experiences odd occurrences around the house, and – ignoring Wan’s warning – sneaks into Uma’s study at night. She finds a photo of Uma, Nirach, and housemaid Ploy; Ploy is Joy’s missing sister. The house is haunted by Ploy’s ghost, and only Joy and Nid can see it.
Joy learns of the circumstances surrounding Ploy’s death from the ghost. Uma and Nirach have a loveless marriage, and each had a separate intimate relationship with Ploy. Ploy and Nirach had a child, Nid, causing resentment from Uma. Later, Ploy suffered a serious accident.
Uma found Ploy first and refused to give or summon aid. Ploy was seemingly dead by the time the rest of the household responded. The household buried Ploy alive, not noticing that she had begun breathing again when their task was nearly complete.
Joy exacts revenge.
The Maid Ending
During a party she murders Uma, Nirach, household staff, and guests, before setting the house on fire and leaving with Nid.
Source: Wikipedia (CC BY-SA 3.0).