When a bloodied and incoherent Jun (Wang Baoqiang) confesses to five murders that have not occurred, the police assume that he's mentally unstable and ignore his claims. Police detective Han (Lau Ching-wan) is investigating a series of gruesome murders, but soon discovers that all is not as it seems and that not only are the murders connected, but that Jun is tied to them in some way.

During Bo and Cheong's wedding reception, a video clip intending to show their journey of love suddenly flashes a clip of Cheong being intimate with another woman. This leads to the cancellation of the wedding. A year has passed and the single Bo and flirty Cheong maintains their relationship as good friends. One day, the womanizer Cheong brings the conservative Bo to a wife swapping party, at the party, they meet Kit and his wife Man Lai. The four developed a romantic and passionate relationship.

An imperial guard and his three traitorous childhood friends ordered to hunt him down get accidentally buried and kept frozen in time. 400 years later, they are defrosted continuing the battle they left behind.

The Narranmoda Boarding School is strict for girls and has rigid rules of behavior, but the headmaster accepts four male students to improve the income of the school. However, the boys are segregated from the girls and the inspector Miss Fong keeps them under the surveillance of the dedicated monitor student Ho Yat-Man. The urban legend tells that the school is haunted and when students break the school rules, they are called to the director office and vanishes or are found dead.

In this prequel to the original, a bloody power struggle among the Triads coincides with the 1997 handover of Hong Kong, setting up the events of the first film.