Most new immigrants are always involved in the activities of gangs. Although some of them are very smart and have established good business, people still call them "Big Circle Guys" indicating that they are outsiders to us. Ching Chi Kuk had come to Hong Kong with his brother Ching Chi Pang, sister Ching Siu Ming and brother-in-law Chi Wai since the middle seventies. Within a few years, Kuk being smart enough, had become well-known among the gangs. Once in an activity, Kuk was arrested and confessed guilty for his boss. Kuk was sent to prison and became a scapegoat. When he was released from the prison, Kuk decided to turn over a new life. During Kuk's imprisonment, his brother Pang joined the gang...

大批新移民涌入香港，他们当中不乏好勇斗狠之徙，不少与本地黑社会同流合污，但毕竟他们都被视为外人，称“大圈仔”。程志鹄（徐少强 饰）和程志鹏（关礼杰 饰）两兄弟是大陆新移民，与妹程少鸣（谢宁 饰）及妹夫志伟（刘家辉 饰）于七十年代中来港谋生；鹄因为有过人的胆色和身手，于黑道打出名堂，但“大圈仔”毕竟逃不出作为被利用者的厄运。在一次行动中鹄替老大顶罪入狱，他出狱后决心脱离黑道；而鹏在短短几年间步兄长的后尘……