'Paap Punya' is Manglu's story. Manglu is a worker in a tea estate who is dedicated to his master. He hands over his son to his master when his wife delivers a dead child. Manglu brings up a deserted child as his own. Manglu's own son Rakesh grows up to be a spoil brat while David his foster son grows up to be a good boy. Rakesh is jealous of David. Their enmity intensifies when David falls in love with Rakesh's fiancee and their real identities are revealed. Manglu murders Rakesh trying to save David and is jailed.