Brij Mohan (36), a hosiery shop owner in a busy Delhi market, desperately wants to change his life. He is fed up of his ball-crusher wife and mounting debts. In order to escape his wretched life, he changes his appearance and adopts a new identity as Amar Sethi, but ends up committing a botched up murder. He runs off with his young girlfriend, hopeful of making a new beginning. Instead, as luck would have it, he finds himself trapped in a web of his own Karma.
墨西哥边境小镇来了一位大镖客（克林特·伊斯特伍德 Clint Eastwood 饰），他得知镇上势不两立的两大帮派罗霍兄弟和镇长巴克斯特相厮杀已久，便决定与两派斡旋，除去镇上恶势力，恢复小镇的平静。他目击罗霍兄弟劫杀了一队士兵并私占黄金，于是利用两具士兵尸体吸引巴克斯特来寻找罗霍兄弟的罪证。同时，他又将消息透露给罗霍兄弟，导致双方展开了一场激烈枪战。乔在两派激战时找到了黄金，并发现被罗霍兄弟囚禁的女人玛利索，他将玛利索交给巴克斯特，换回了在激战中被捕获的儿子安东尼奥。但后来他得知玛利索是被罗霍家的雷蒙抢占，于是设法救出了她，帮助她与丈夫孩子一起逃出镇子。深爱着玛利索的雷蒙发现心爱的女人被放走，便认定是巴克斯特一家所为，于是展开了疯狂的报复。究竟两大帮派谁胜谁负，作为中间人的大镖客能否实现恢复小镇和平的计划？