The story of Ruby Castle is told in snapshots and fleeting glimpses and secret histories, in tales repeated and reinvented by those who fall under the horror film actress' spell: her childhood sweetheart; an antiquarian bookseller with a passion for magical artefacts; the mistress of the poet who was once Castle's lover; a young girl in a future Russia who dreams of the stars. As worlds collide, the boundaries between the real and the fantastic begin to break down. Is Ruby Castle a living person or a collective fantasy? By the time the final page of Ruby is turned, the world that Castle created through her films has become dangerously indistinguishable from our own.