The story of the Salmon and Fionn Mac Cumhaill.
"Finegas taught the druidic arts to Fionn but he never lost his hope that one day he would catch the Salmon of Knowledge. Every day he would cast his line into the Boyne in the hope of hooking the fish and suddenly one day he hooked a giant of a salmon. He knew immediately that it was the transformed Fintan. He called out in joy and pulled the fish on to the river bank. Calling Fionn he demanded the lad set about building a fire and cooking the fish. He warned the young man not to eat any of the fish and the boy gave his promise...."