The sea is a cruel mistress, as some may say. However, for the oldest family on Idir na Farraigí, the sea is not cruel at all - she is of them, and they are of her. Bronagh Ó Loinsigh, the last female child of the descendants of Muirín, Mother of the Island, has returned home to learn of her family's history after years of exile to the mainland. There, under the tutelage of her estranged, but loving, mother, Bronagh learns that she is not only the daughter of a sea-faring family but a daughter of the sea Herself.