The story follows Effy Sayre, a young architecture student at a prestigious university where women are barred from studying literature. Haunted since childhood by visions of the Fairy King, Effy finds solace in a book called Angharad, an epic written by the late Emrys Myrddin. When a contest is announced to redesign the author’s crumbling family estate, Effy travels to the remote, coastal Hiraeth Manor. There, she encounters Preston Héloury, a cynical literature scholar determined to prove that her favorite author was a fraud. As the two rivals investigate the manor’s secrets, they discover that both the house and the myths surrounding it hide dark, magical forces that threaten to pull them under.