A university professor experiences a fugue state lasting five years, during which his body is occupied by a brilliant mind from Earth's deep past. Upon recovering, he is haunted by memories of a vast library city and a race of cone-shaped beings who master time and space. His journey to the Australian desert confirms that his nightmares are actually memories of a civilization that predates humanity. The novel is a sweeping sci-fi epic that displaces man from the center of history.