Can a gangster just released from prison use the police to exact revenge on the triad boss responsible for his incarceration? Kong Sai Hau (Michael Miu) returns to Hong Kong after serving 10 years in a Taiwanese prison. He pretends to surrender to To Yik Tin (Lam Lee), the triad boss responsible for his imprisonment, while also working as an informant for police officers Chung Lap Man (Ron Ng) and Lee Pak Kiu (Sammul Chan) to take To Yik Tin down. Kong also tries to use To Yik Tin’s wife, Ching Yeuk Sam (Kathy Chow), to rise up the ranks of the triad but has a tough time gaining the trust of the influential leader Laughing (Michael Tse). When Chung also goes deep undercover within the triad, he meets Kong’s daughter, Yau Yau (Elanne Kang), whose trust he uses to help him move up the ranks of the crime organization. Can the trained undercover agents stop Kong’s plans to topple To Yik Tin and take over the triad? “E.U.” is a 2009 Hong Kong drama series created and produced by Wong Wai Sing. It is the sequel to “On the First Beat” (2007) and the third installment of “The Academy” series.