11-year-old Dong-ku, who is retarded, is the school's water boy until, that is, the school installed a water purifier system. Disappointed, Dong-ku soon learns the school's baseball team needs a water boy and so he decides to join the team.

A group of neuropsychology graduate students work to unlock the potential of the brain. One student, Adam, takes his lab work too far. When his self-induced experiment goes wrong, he unwittingly unlocks repressed memories and begins to be haunted by disturbing visions. As Adam digs deeper, he finds that there is someone who doesn't want him to uncover the sinister truth. Adam and his friends must work together to help him confront his recollections and figure out what is truth and what are lies before it's too late.