Krishna’s parents, Vasudeva and Devaki, were kept in prison right after their marriage, by Devaki’s cousin brother Kamsa. Their seven children born in prison were slain by Kamsa to falsify the prophecy of his death by one of them. Krishna was the eighth. Vasudeva carried newborn Krishna secretly to the cowherd community Gokula. Krishna grew up there as son of Nanda and Yashoda and brother of Balarama.
Kamsa sent Putana, the poison-milk demoness to do away with Krishna. She herself met her end. Krishna the cowherd boy played pranks with the neighbours, played the flute, tamed bulls, killed a poisonous snake in the pool where cattle drank water, led the cowherds to worship the mountain that supported their cattle.
Kamsa pursues Krishna all this while. Finally, he gets Krishna and Balarama to his capital Mathura for wrestling matches. Krishna succeeds in winning them. He puts Kamsa to death and brings Kamsa’s father back to the throne.