The year is 2046 and 82 year old Golden Chicken Kum, spots a heartbroken man planning to take memory loss-pills. Claiming that Hong Kong people have a way of forgetting, she begins to recap part of her life story, starting in 2003 during a time where she was desperately looking for a husband and the SARS outbreak happened.

A horrid crime was committed at a wedding reception and bridesmaid Chi Ching was the lone eyewitness. At the police station, she recognised the suspect, Suen Ling, in a line up. She also discovered the affair between this stranger and her lover. All of a sudden the emotional turmoil surrounding her chronic illness resurfaced and quickly grew beyond control.

Various government departments of the Hong Kong Special Administrative Region have been criticised heavily by the public. The Commissioner welcomes the proposal of "Sunshine Cops" from public relations officer Geena to enhance the image of Hong Kong's finest. Both Lemon and Sammy have recently completed their Police Tactical Unit (PTU) training. They look like movie stars and are fit and ready to conquer the world. They are selected to represent PTU in the internal audition for "Sunshine Cops" and contest against elite from other units like Criminal Investigation Department and Task Force, etc. The competition is tough but they prevail.

Two grieving mothers resurrect a scam ringleader to avenge their daughters — but as painful truths emerge, justice slips from their reach.

A gang of South Korean thieves team up with a Hong Kong crew to steal a diamond necklace from a heavily-guarded casino safe in Macau. As the cops close in, old betrayals — and misunderstandings — resurface.