"Line Walker 2: Invisible Spy" is a Hong Kong action thriller film released in 2019. It serves as a sequel to the 2016 film "Line Walker," continuing the story of undercover police officers. The film features a mix of intense action sequences and intricate plot twists, focusing on the challenges faced by law enforcement in combating organized crime. The narrative revolves around the character Cheng Shun, played by Louis Koo, who is tasked with infiltrating a criminal organization. As he navigates the dangerous world of espionage, he encounters various allies and adversaries, leading to a gripping exploration of loyalty and betrayal.