The autumn castle - Kim Wilkins

Berlin in autumn: Christine Starlight is living in an artists' colony sponsored by the art philanthropist Immanuel Z, himself a sculptor, in the crumbling urban shadows of the old east. Her lover Jude is a painter; his beauty and patience help her bear the chronic pain that is a legacy of the car crash that crippled her and killed her beloved parents.
Out of the blue comes a crimson-haired beauty, who presides over a land where a witch dwells in a well, a wolf is the queen's counsellor and fate turns on the fall of an autumn leaf. For a brief span, while the lands of faery and mortal man march hand in hand, Queen Mayfridh has taken the chance to seek out Christine, her childhood friend.
But dealings with faeryland are never simple: as Christine yearns for Mayfridfh's world, where mortals feel no pain, so Mayfridh in turn is becoming addicted to Christine's, where there are tastes and textures and the danger of forbidden love.
And as secrets and jealousies and betrayals begin to unpick the threads that bind their lives, so yet another danger stalks them: the cruel and brilliant billionaire Immanuel Z. He too has faery blood, but he has a different use for Mayfridh and her kind: he is hunting faery bones for the grandest sculpture of them all . . .