Chan Wing Yan, a young police officer, has been sent undercover as a mole in the local mafia. Lau Kin Ming, a young mafia member, infiltrates the police force. Years later, their older counterparts, Chen Wing Yan and Inspector Lau Kin Ming, respectively, race against time to expose the mole within their midst.

A reforming ex-gangster tries to reconcile with his estranged policeman brother, but the ties to his former gang are difficult to break.

The drama follows the lives of undercover police agents who must live a double life in secrecy. Not knowing when they can return to their normal life, they must also endure the constant fear of being uncovered by those they are assigned to infiltrate. However, this time their lives are put in danger when it is discovered that a mole lives within the police force.

Hong Kong cop Chan Ka-Kui returns, working with Interpol to track down and arrest an illegal weapons dealer. Chan later realizes that things are not as simple as they appear and soon finds himself to be a pawn of an organization posing as Russian intelligence.

Obsessive master thief Neil McCauley leads a top-notch crew on various daring heists throughout Los Angeles while determined detective Vincent Hanna pursues him without rest. Each man recognizes and respects the ability and the dedication of the other even though they are aware their cat-and-mouse game may end in violence.

女主角明依（薛佳凝 饰）是位失明的单身母亲，带着女儿欢欢独自经营一家花店，后经过眼科医生高木（陈浩民 饰）的治疗，明依得以重见光明。为了使自己和女儿都有一个全新的开始，明依在高木的帮助下搬进了一座百年古宅，但没想到的是，母女二人也由此卷入一系列怪事之中。眼盲时留不住真爱，眼明时辨不出真心，这扇厚重的大门背后究竟藏着什么娟姨（罗兰 饰）想拼命保守的秘密？