So, this is one of the beautiful Leela of the Supreme Godhead, Lord Krishna. 

This is the story when Shree Krishna and Balrama completed his education from Guru Sandipani, Shree Krishna and Balrama go to their guru and ask for their GURU DAKSHINA, where guru take a proise from both to use their education wisely then both ask Mata Sumukhi Devi, what they can offer to her , firstly she refuses but after forcing too much she ask to bring her son Punardatta back, who died in sea.

Shree Krishna and Balrama go to the sea where Punardatta died, Shree Krishna invite the Varuna Deva with the thuddle of his bow, and orders him to return Punardatta, Varuna Deva said he do not have Punardatta but an asura called Panchjanya who eats human who came to the coast of sea and Punardatta might be eaten by him. Now he is resting in his Conch.

As per Varuna deva said Shree Krishna and Balrama dive in the se and start finding the conch shell in which asura Panchjanya is resting, after some time they find the shell and said see Panchjanya your end is come to meet you and angry Panchjanya come out of his conch shell and start yelling.

Panchjanya is a giant, so in order t fight him Shree Krishna grow his size same as asura and throw some punches, when Panchjanya realizes today he is going to die, he start running but Shree Krishna chased him and both break into Sword fight in which Shree Krishna cut Panchjanya into half and Balrama find that Punardatta is not inside his stomach.

Shree Krishna take Panchjanya's conch shell and played it, Whole universe bow down to the supreme Godhead and Shree Krishna said from now this Panchjanya conch shell will always be played at the victory of Dharama and go to the Yamapuri.

Shree Krishna and Balrama reched Yamapuri, when they both going to enter in it the guards stop them and ask where is Yamdutta who take you up there and Lord replied we are not dead and we can never be dead so guard said one can not enter Yamapuri with material bodies so Shree Krishna politely replied that say to Yamaraja please come out and meet them, Guards started laughing and refuse to call him than Shree Krishna played Panchjanya conch shell and its sound shaken the whole Yamapuri and tension is created.

Yamaraja get angry and wanted to see who is the person in all universe who shaken the whole Yampuri and he came out and see two young brahmins, and Yamaraja realizes these two boys are none other but Narayan and Sheshnaga himself, Yamaraj fall on his knees and bow down aboe the Supreme Godhead and ask Lord how he can serve them.

Shree Krishna said I want you to give Punardatta back, Yamaraj replies but Lord i will just able to give his soul to you because i am not powerful enough to return him with his body by saying this Yamaraj give Punardatta's souk to Lord and they left Yamapuri with Punardatta's soul.

Before going to Mata Sumukhi Devi, Shree Krishna provide Punardatta's soul his body and left him under a tree, when Punardatta open his eyes he see two brahmins giving him the medicine and ask are you Punardatta ? because his parents send us to find their son and they take him to his home.

Finally Shree Krishna and Balrama return to Ashrama and give Punardatta back to Guru Sandipani and Mata Sumukhi Devi when Mata see Punardatta she break into tears and hugs Punardatta, She blessed Shree Krishna and said may God provide you the power of fading the all sorrows of people like you fade my sorrow and Guru Sandipani said you are not human you must be a Deva who is living with curse, so my Lord Shiva remove that curse from you and I am ready to take your Curse and make you free from it.