The Owl Service (1969)

Gwyn and Alison read The Mabinogion and Gwyn explains the ancient legend of Blodeuwedd and the Stone of Gronw; Blodeuwedd was created out of flowers as a wife for the hero, Lleu, but was turned into an owl after she had been unfaithful with a man called Gronw. Huw thinks there might be a connection between the plates and the legend.