Pilot Premnath (1978)

Pilot Premnath (Sivaji Ganesan) has three children — two sons (Vijayakumar and JaiGanesh) and a blind daughter (Sridevi). He is closely attached to his children, especially his daughter. His wife (Malini) dies in an accident.

The deceased wife continues to live in Premnath's heart, and every time he returns from a flight journey, he goes to their room, and sees her in his mind’s eye. Once while talking about her in the room with his co-pilot (Thengai Srinivasan), he shows him the bundle of her letters. One letter is found, not posted. In it, the wife states that one of the three children was not born to her.

The world around him shatters and it is then he breaks into the song "Who Is The Black Sheep?" The suspense is revealed later. Premnath goes to America for training, leaving his pregnant wife behind. She delivers a stillborn child. Simultaneously, his friend Balu’s (Major Sundararajan) wife gives birth to a blind baby girl and to prevent tragedy in Premnath’s family, Balu substitutes his baby with Premnath’s.

The two sons find sweethearts (Jayachitra and Satyapriya) and the daughter falls in love with a young man (Prem Anand), who saves her from a thief near a shop. All get married and happiness is restored once more in the household.