1960-70s Hong Kong, corruption and crime ran rampant under the shadow of triad dominance. Amidst this turmoil, an upright and honest man named Xu Lei (played by Wang Haoxuan) joined the police force due to his humble background, trading his school days for a police uniform. Despite starting off as an ordinary officer, he gained notoriety for solving a high-profile burglary case, which brought him unwanted attention from Long Xue long (Li Zixiong), his uncle and a powerful detective. This displeasure led to ostracization and demotion to the Water Police Department. While handling a chaotic incident, he crossed paths with the wealthy heiress Bai Zhenni (Xu Dongdong), who developed an immediate affection for him. Caught between his longtime girlfriend A Zhen (Yun Qianqian) and the opportunity to escape his dire circumstances presented by Bai Zhenni, Xu Lei faces a challenging choice between power and love. Can he rise above adversity, climb the ranks, and become an iconic detective in the annals of Hong Kong history...?
追龙番外篇之十亿探长影评