The Only Supporter(1976)

Karim introduces Abi to a girl named Nasrin, who takes care of his blind son Saeed and sings in Abbas's cafe. Karim warns Abi against continuing his relationship with Nasrin, and upon meeting Nasrin, he realizes that she is the woman he abandoned in Bandar years ago and that Saeed is his own son. The two reconcile, and Abi suspects that Karim has betrayed him. On Abbas's advice, Abi drags Karim to a secluded house to take revenge on him; but Nasrin explains to Abi the story of her and Karim's long-standing love. Abi enters the fray and is stabbed by Abbas.