E.U.

After ten years behind the bars in Taiwan, Kong Sai-Hao (Michael Miu) finally returns to Hong Kong. Besides hoping to find his daughter Yau-Yau (Elanne Kong) to mend their relationship, he also plans for revenge. On one hand, he pretends to surrender to triad boss To Yik-Tin (Lam Lee), the man who caused him to be jailed. On the other hand, he tries to gain trust from police officers Chung Lap-Man (Ron Ng) and Lee Pak-Kiu (Sammul Chan). Pak-Kiu refuses to have a criminal as his friend, but Lap-Man becomes an undercover police in Sai-Hao's gang. Along with Sai-Hao, they overrule Yik-Tin and take over the mafia, and the two develop a misconcepted mentor-student relationship. Unfortunately, Lap-Man gets fired from the police force before he can finish his mission in the mafia. He becomes Sai-Hao's people and turns his back against the police force....