Singer-songwriter Fflur Dafydd has won the Oxfam Hay Prize for emerging writers for her first novel in English.
Twenty Thousand Saints, set on Bardsey Island, looks at how young women, starved of men as the boats stop bringing them, turn to each other.
It is the second novel the 30-year-old has set there after spending six weeks as a writer-in-residence on the island.
The earlier novel was the Welsh-language Atyniad, which was awarded the the prose medal at the 2006 Eisteddfod.
The book, which was published in October last year, has already won critical acclaim.
She said, "I know, without being immodest, that my novel is a good read, but it's something else for others to recognise in a thriller set on Bardsey island the deeper comments I wanted to make about privacy, loss, disillusion, language and identity."
Fflur Dafydd is also an academic critic specialising in the poetry of RS Thomas.
She lectures in creative writing at Swansea University and lives in Carmarthen.
As a singer-songwriter, she has released two albums.