In a bustling city, a series of seemingly unconnected murders baffles the police force. A veteran cop, known for his reserved demeanor and martial arts prowess, teams up with an enthusiastic yet reckless rookie. Together, they embark on a mission to uncover the truth behind the deaths. The victims appear to die joyfully with smiles on their faces, a curious detail that leads the detectives to probe deeper into their private lives. As they investigate, they discover a connection between the deceased centering around the same circle of acquaintances and activities. Their investigation leads them through a maze of suspects, from wealthy socialites to underground martial artists.

As they delve deeper, tension rises between the experienced cop's methodical approach and the rookie's energetic impulsiveness. The dynamic duo must navigate confrontations with elusive suspects, all while fending off perilous situations with their wit and fighting skills. Just as they seem to get a grasp on the case, new twists compound their challenges, further entangling them in a complex web of deception and danger. The trials they face test their partnership, pushing them to blend their distinct approaches to solve the mystery.