Rosa accepts a job as a maid in Singapore, helping to care for the Teo family's mentally disabled son. But her arrival turns out to be catastrophically ill-timed: It's the seventh month of the year, which, according to local superstitions, is when the forces of the underworld are capable of unleashing their evil on earth. Soon, the newcomer finds herself beset by nightmarish visions about the horrible fate of the family's previous maid.