Oíche amháin imíonn Conall leis chuig bainis i dtigh Chulainn Gabha, agus i ngan fhios dó leanann a mhac é. Fad is atá an buachaill óg ag imirt iomána taobh le hionad na bainise, buaileann sé agus maraíonn sé cú trí thimpiste. Seo é an cú iomráiteach a chosain clann Chulainn ó thriúr fathach go rialta. Téann an buachaillín ar tóir na bhfathach seo chun a fhiachas a aisíoc, agus nuair a éiríonn leis, glacann sé áit an chú mar chosainteoir tí Chulainn as sin amach.
Cú Chulainn is perhaps the most famous of the heroes in Irish Mythology, however in this story, retold by Máirtín Mac Grianna, we first learn about Conall Cearnach – a man held in high esteem at the time, and how he raised and saved a child from a doubtful future.
One evening Conall accepts an invitation to a wedding at the house of Culann Gabha, and unbeknown to him his son follows him there. The boy begins to play hurling outside while waiting for the party to end and accidentally hits and kills a hound; the very hound that protects Culann’s house from three giants nearby. To repay his debt the boy goes in search of the giants, and when he succeeds in killing them he himself becomes the protector of Culann’c clan, replacing the hound.