The movie begins with the tale of a man called Zafar Khan, who falls in love a girl called Salma and will do anything to marry her. He is ready to even take recourse to evil ways to get her for himself. However, she does not want him, and nor does her father think of Zafar as fit to marry his daughter. Zafar has his fingers in many a criminal pie and is finally arrested and imprisoned for 10 years
However, later, when he is released from prison, he seeks out Salma and sees that she is married to a good man named Aslam Khan. Zafar Khan, tries to convince Salma to marry him but Salma refuses. Zafar takes revenge by flooding the area in which Salma lives, killing her father, injuring Aslam and Salma, causing her to lose her memory. During this time, Salma is also separated from her young son, Iqbal. Zafar kidnaps Salma and tells the world that she is his wife. He also adopts an infant from an orphanage in Kanpur, a boy named Sunny, for Salma to raise on the advice of a psychiatrist.
In the meanwhile, Iqbal is reunited with his uncle, who has lost his wife and son in the flood. The uncle raises Iqbal as his own son.
Years pass by, and Iqbal and his uncle work as coolies. Iqbal grows up to be an attractive man with a strong personality (Amitabh Bachchan), and is becomes the leader of the local coolies. He organizes a labor strike, which brings the station to its knees. A young, budding reporter, named Sunny (Rishi Kapoor), is covering the story. While speaking to Sunny, Iqbal sees a picture of Sunny's mother who turns out to be Salma. Iqbal rushes to Salma's house to see her after all these years, but upon meeting her son, she has no recollection of him. Zafar is infuriated by this and has his guards severely beat him, while he takes Salma to the psychiatrist to administer electric shocks on her so that her memory never returns. Iqbal and Sunny become friends, and both find their partners in love and life (Rati Agnihotri and Soma Anand).
In the end, Iqbal finds himself in a fight to the death with Zafar. What will happen to Zafar? Will love and the truth endure this passage of time?