Arjun Singh (Amitabh Bachchan) has singlehandedly been brought up by his grandfather, whom he fondly addresses as Daddu (Om Prakash) as his mother (Waheeda Rehman) leaves him as a child. He is a simpleton and is totally dependent on his grandfather for everything. Hence, his daddu decides that he needs to gain some amount of independence and sends him into the city.
Arjun Singh, goes into the city and meets Bhairon (Ram P. Sethi) who finds him a job in a 5-star hotel owned by Raja (Shashi Kapoor). While in the hotel, Arjun meets Poonam (Smita Patil) and falls in love with her.
During this time, many attempts are made to kill Raja by Girdar Singh (Satyendra Kapoor) and his son Ranjeet (Ranjeet). These attempts are thwarted by Arjun, who has in time, been made the personal bodyguard for Raja. Will he be able to save Raja from these attacks? Is Raja's foster mother involved in these attacks, and is she actually Arjun's estranged mother?