A shape-changing priestess and a time-traveling relic hunter quest together for the Holy Grail in Kearney's far-fetched series debut. Lady Cael, high priestess of the planet Pendragon, is the only woman of her generation who can shift forms from human to dragon. Lucan Roarke is from a future Earth where most of the population is sterile. To save his people, Lucan travels to Pendragon seeking the legendary Grail. When Pendragon's military frames Lucan and Cael for the murder of their colleagues,the two are forced to depend on each other to recover the Grail and survive. Kearney (Dancing with Fire) writes a credibly (and explicitly) passionate and rough romance, but factual errors and a mishmash of myth will jar readers familiar with Arthurian legend, leaving this solely for fans of sexy space opera intrigue. (Sept.)