In Sham Shui Po, the most renowned red-light area in Hong Kong, Li (played by Carrie Ng) owns several apartments in a building, which she rents out to sex workers. To these women, Li is more than just a landlord; she is a friend. Together, they strive to attract clients and improve their circumstances. However, they remain unaware of the looming danger. The disappearance of Ping, a prostitute living with her young daughter, marks the beginning of their troubles. As Li searches for Ping, she uncovers a disturbing pattern of missing sex workers from the building, none of whom have been found. The building seems cut off from the outside world, and a series of murders ensues. Li and the other women must locate Ping and outsmart the unseen killer. As more clues about the murderer’s identity come to light, a tragic secret buried for over two decades begins to emerge.