Keung is a middle-age office worker who leads a life of non-existence among his colleagues in spite of being an experienced worker. One day, he is befriended by Sun, a new teenage recruit. This new apprentice gives Keung the ego boost he so needed because Sun needs him for advice. However this friendship begins to fall apart when Sun also becomes friendly with other colleagues and his gained experience also makes him less dependent on Keung. The fallout makes Keung angry with jealousy and acts possessively until at the breaking point, Keung kills Sun. Only then is the secret revealed about the truth between Keung and Sun.