Cast
Amitabh Bachchan as Arjun Singh
Shashi Kapoor as Raja Singh
Smita Patil as Poonam
Parveen Babi as Nisha
Waheeda Rehman as Savitri
Om Prakash as Dashrath Singh "Daddu"
Ranjeet as Ranjeet Singh
Satyen Kappu as Girdhar Singh
Viju Khote as Talvar Singh
Ram Sethi as Bhairon
Kamal Kapoor as Raja Sahib
Suresh Oberoi as Bheem Singh
Ashalata Wabgaonkar as Nisha's GrandMother
Plot (Spoiler Alert!)
Bhim Singh (Suresh Oberoi) works as a manager and personal bodyguard to Seth Raja Singh (Kamal Kapoor) and saves him from many murder attempts planned by Raja's step brother, Girdhar Singh (Satyen Kappu). One day Raja Singh appoints Savitri (Waheeda Rehman), Bhim Singh's wife as trustee to their property and guardian to his toddler son Raja Kumar. On the same day, he and Bhim Singh die at the hands of Girdhar Singh. Savitri promises her husband that she would take care of Raja Kumar at any rate. Everyone including Bhim Singh's father Dashrath Singh (Om Prakash) blames Savitri thinking that she killed her husband and employer for money. Savitri hands over young Arjun to Dashrath Singh and settles herself as Raja Kumar's mother to protect him.
Later Arjun (Amitabh Bachchan) grows up to be a naive youngster under the care of Dashrath Singh. He moves to the city to build his life on his own and joins as a bellboy in a five star restaurant. There he meets Poonam (Smita Patil) and they both fall in love. That hotel is owned by Raja Kumar (Shashi Kapoor) and run by Savitri. Hotel manager Ranjit Singh (Ranjeet) is the son of Girdhar Singh and plans to kill Raja. They manage to show Savitri as a culprit and Raja believes that and suspects Savitri.
Gradually Arjun learns that Savitri is actually his, not Raja's mother and swears that he would protect Raja at any rate, just like his father did. Meanwhile, Raja meets a beautiful young dancer Nisha (Parveen Babi) and gets attracted to her. She is actually hired by Ranjit Singh to kill Raja, but Nisha falls in love with Raja and couldn't kill him. Finally she arranges a party on a boat to execute her plan, but Arjun foils it.
Finally goons kidnap Arjun's and Raja's family members and blackmail them to transfer all his property to Ranjit's name. Arjun and Raja beat all bad guys and save their loved ones. Raja marries Nisha and Arjun marries Poonam at the end and they reconcile with their mother Savitri.