The police set up a department called "2002" to deal with wandering ghosts that harm the world. Chao (Nicholas Tse) is a human with yin and yang eyes, and Sam (Sam Lee) is a ghost. The entire department consists of this person and this ghost. During this period, they encountered various ghosts that harmed humans and conquered them one by one. Later, Chao was entrusted by the deceased Sipo to help take care of the hospitalized granddaughter Rain (Caihua Li). Chao fell in love with a nurse in the hospital. But he had to concentrate on fighting the water ghost with Sam, and this battle would determine their life and death.