A depressed but hard-working advertising executive loses her job after having her ideas stolen by her colleagues, then after falling asleep, she awakes to relive the day repeatedly until she discovers more about herself and her colleagues.

Employees working at a high rise building begin encountering a series of strange occurrences. Ken, a recent hire who attracts to the lovely, but spiritually harried Shan. Meanwhile, Pat is apparently terrorized by the evil demon who resides in the last stall of the woman's bathroom. And Richard, a mean boss of another company in the same building, wants to get rid of his long-time employee Mary and begins to suspect that his entire staff has become ghosts.

Skinflint businessman Richard (Leung) doesn't feel bad when he sacks his employees and secretary to cut unnecessary costs. He also doesn't bat an eyelid when his gold-digging girlfriend leaves after he refuses to give her money. She gets her revenge by cancelling his credit cards and giving away his furniture. Suddenly destitute, he's forced to rely on the generosity of Choi (Shu Qi), a good Samaritan who helps him out even though she thinks he's a scumbag who makes a habit of cheating women out of money.

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.