"Kumarn" tells a story of Ging who takes her son for a vacation in a forest. One night, a stranger break into her house and kidnaps her son. Ging tells the police and finds out that the stranger is an undertaker at a temple. The accused undertaker claims he never breaks into her house so Ging goes into the forest to seek help from a monk on pilgrimage but instead witnesses the undertaker performing an ancient ritual of taking a baby out of a dead pregnant woman and making it KUMARN, a guardian doll. Being chased after by the undertaker, Ging loses her mind. Nop, Ging’s boyfriend and Pam, a nurse and also his close friend, come to the house and see Ging unstable holding tight to a clay doll she believes her son is trapped in it. Nop and Pam force to send Ging to asylum without realizing that it leads to a tragic consequence.