The Maid’s Caul

When the same girl appears in every dream, Zoa sets out to find her.
Three times he thinks he’s found her, only for each girl to insist he must be seeking her far more beautiful sister.
At the palace of the girls’ mother, the queen has been deserted by everyone but a maid born with an irremovable caul; a maid who serves yet never sees a prisoner held in a high tower.
Is this where Zoa will find the girl of his dreams?