Blodeuwedd

The hero Lleu Llaw Gyffes has been placed under a tynged ("doom") by his mother, Arianrhod, that he may never have a human wife.

He reveals to her that he can only be killed at dusk, wrapped in a net, with one foot on a bath and one on a black goat, by a riverbank and by a spear forged for a year during the hours when everyone is at Mass.

Gwydion and Math nurse Lleu back to health before mustering Gwynedd and reclaiming his lands from Gronw and Blodeuwedd.

Lleu refuses, demanding that Gronw must stand on the bank of the River Cynfael and receive a blow from his spear.

Eventually, Gronw agrees to receive the blow on the condition that he may place a large stone between himself and Lleu.