Warring undercover cops, Apple (Priscilla Wong) and Tai Shu (Edwin Siu) pause mid-fight when he spots his father. Turns out that Dad is the new estate security guard. Tai Shu peers out while pressed up against a wall, and Apple becomes aware of how close they are. She comes to her senses, and shoves him away.
Tai Shu goes home, where his father is still bitching about his estranged wife who used the down payment on an apartment for plastic surgery then abandoned the family 20 years ago. When Tai Shu’s mood becomes grim, his father changes the subject. Tai Shu finds out that his father’s reassignment to the apartment where he is posted, is for the foreseeable future.
Housewife, Dan Dan (Mandy Wong) is having a mutually supportive moment on the couch with her husband. It seems the perfect time for Dan Dan to bring up the idea of a second child, but her husband does not believe that they can afford it.
The older women of the estate are doing tai chi when Apple jogs by. She is attempting to ingratiate herself with the mother-in-law of neighbour, Fung Nei (Kaki Leung), when Fung Nei arrives. Fung Nei hands out coupons to promote her new beauty store. However, her mother-in-law is not promising that she will be present at the store’s grand opening.
Apple arrives home, and walks in on Tai Shu peeing then witnesses him scratching himself. She promptly writes up cohabitation rules that covers a range of his offences. Tai Shu scoffs at the list, then goes to his job as estate plumber.
While working on a resident’s plumbing, Tai Shu learns about Maruko, a young resident who is left home alone. Her father is deceased and her mother is busy working, but no one has informed the authorities. Tai Shu checks in on the girl, but Maruko closes the door on him.
Tai Shu’s gassy partner, Ga Lun gets a job as a security guard at the apartment complex in order to keep an eye on Tai Shu’s father. He is also able to provide Tai Shu with his father’s schedule so that Tai Shu can avoid running into him.
During the grand opening of Fung Nei’s beauty shop, Dan Dan suddenly bestows Apple with the prize of a free facial. It turns out to be a ploy to ensure that Apple is nowhere near her apartment while Dan Dan and fellow housewife, Lin Heung (Rachel Kan) surveys the home of comatose criminal, Wan. Using Lin Heung’s phone propped on her son’s remote control car, the housewives find Wan’s document case. Unfortunately, Lin Heung crashes the car, and both it and the phone are irretrievable.
Tai Shu tails Maruko, then feels compelled to step in when another child’s mother falsely accuses her of theft. He treats her to a meal, and finds out that Maruko is locked out of her home until her mother gets off work.
During her facial, Apple digs for the source of the funds Fung Nei used to open her shop. Fung Nei nervously claims that it all came from savings, and loans from family. Apple is called away by Valentino, the flirty cop whose place was taken by Tai Shu in the undercover operation. He confirms Apple’s suspicions that Fung Nei has no record of savings nor a loan.
Fung Nei receives a visit from a triad member who has come to extort protection money. He warns her against contacting the police, then promises to return for payment. However, when it turns out that Ga Lun was Fung Nei’s hometown neighbour, she confides in him, not realizing that he is a policeman. He tells her to call him when the triad return.
Coming home, Apple hears the creepy ring tone of Lin Heung’s phone emanating from Wan’s apartment. Apple thinks she hears ghosts, Tai Shu acts skeptical, and Maruko jumps out of the bedroom with a frightening amount of Apple’s makeup on.
Apple gets dared into cooking dinner for Tai Shu and Maruko. She ends up following her mother’s instructions, which play out like a TV cooking show via her smartphone. Tai Shu buys some roast duck as insurance, but it turns out that they need not have worried; Apple’s dishes look like a mess, but they taste good.
Lin Heung gets an earful from her son after he finds out that she has signed him up to study abroad without telling him. She gets some brownie points for buying him a new remote control car, but he freaks out again after Lin Heung claims that she threw out his old one. The car that is actually stuck in Wan’s apartment was his father’s last birthday gift to him before their divorce.
After a phone call to her mother, Apple again hears Lin Heung’s creepy ring tone coming out of Wan’s apartment. Tai Shu joins her outside, but hears nothing.
Back in the apartment, Maruko suddenly remembers that her mother will not be home that night, and convinces Apple and Tai Shu to let her sleep on the couch. Thus, Tai Shu is kicked off the couch, and into Apple’s bedroom. Apple then kicks him out of bed, and onto the floor.
In the middle of the night, Apple is woken up by ghostly wailing. When it is obvious that Tai Shu is not the source of the noise, she is left scared and perplexed.
As usual, Tai Shu is non-stop entertaining with his boorish ways. All other story lines are stop gaps until the next scene featuring Tai Shu and Apple hating on each other. Here are screen captures of Tai Shu making reference to Apple’s chest, enlisting support for scratching oneself, and warning Maruko against Apple’s cooking.