The movie opens to scenes of a little boy and his father at a meat shop. The boy is shown smuggling heads and bodies of various animals home and preserving them in jars under his bed. Upon discovering this, his father beats him. When he grows up, he kills his father. The scene then shifts to the present.
In the present, the abduction and murder of two little girls of Trivandrum in succession, with no apparent motive makes investigation officer ACP Rithika Xavier (Mamta Mohandas) suspect a serial killer. She requests a forensic team but finds it awkward that the personnel assigned is the young Samuel John Kattookkaaran (Tovino Thomas), who happens to be the younger brother of her estranged husband Xavier John Kattookkaaran (Saiju Kurup). It is shown that the couple broke away after the loss of one of their children apparently due to carelessness and also that the surviving child Nayana consults a psychologist, Dr. Alphonse Kurien (Giju John).
Samuel concludes the killer seems able to move comfortably through a four-foot tunnel but unable to dispose of the body over a five feet wall, and able to blend inconspicuously in a compound of children, hence it must be a child. Though dismissive at first, Rithika Xavier is forced to accept Samuel’s theory as an eyewitness shortly confirms a little boy dumping the dead body, though she does so in grace. Further victims are added to the list even as the police publish a sketch of the killer-child as described by the witness.