1998年，以硕泰（金允石 饰）为首的五人团伙“白魅”绑架了某位高权重之人的幼子。行动失败后，他们并未撕票，而是将男孩收作养子，并有意识地培养起成为杀手接班人。转眼将近二十年时光过去，得名华颐（吕珍九 饰）的男孩已经长大，成为清秀帅气的高中生。硕泰遵照上线的指示犯下一连串恶性罪案，他有意让华颐踏入此道，但男孩自幼便仿佛具有能看见怪物的能力，以至于在关键时刻总功亏一篑。在某次行动时，华颐意外获悉自己的身世之谜，可在硕泰不得不开枪射向和他有血缘关系的男人。 一意孤行的硕泰，越来越不满的上线组织，始终追查白魅的警官，华颐的命运被卷入漩涡之中……Hwayi is a boy living in a farm village, who was raised by 5 fathers who were famous criminals. One day, the group is commissioned to kill a man named Lim and his wife. While the rest of the group feel something odd about this particular contact, Suk-tae is adamant to carry out this job with Hwayi in tow. During the job Hwayi discovers a photograph of a child in Lim's house. Eventually, Suk-tae hands his gun to Hwayi and he is forced to pull the trigger. He becomes ill after committing his first kill and realizes that the boy in the photograph looks uncannily familiar.
