The Owl Service

Blurb

The Owl Service is a low fantasy novel for young adults by Alan Garner, published by Collins in 1967. Set in modern Wales, it is an adaptation of the story of the mythical Welsh woman Blodeuwedd, an "expression of the myth" in the author's words.
Garner won the annual Carnegie Medal from the Library Association, recognising the year's best children's book by a British author. It was named one of the top ten Medal-winning works for the 70th anniversary celebration in 2007, selected by a panel to compose the ballot for a public election of the all-time favourite. Garner also won the second annual Guardian Children's Fiction Prize, a similar award that authors may not win twice. Six books have won both awards in 45 years through 2011.
The mythical Blodeuwedd is featured in the Fourth Branch of the Mabinogi. She is a woman created from flowers by Math and Gwydion, for a man cursed to take no human wife. She betrays that husband Lleu in favour of another man, Gronw, and is turned into an owl as punishment for inducing Gronw to kill Lleu. In Garner's tale three teenagers find themselves re-enacting the story.