Althalus is a young thief and occasional killer known for his skill and incredible luck. A number of capers end without much monetary reward for him, until he stumbles into a shrine built to the fertility goddess Dweia. Soon afterward he meets with the wizard Ghend, who hires him to steal the Book, a magical tome that can be found in the bizarre House at the End of the World. There, Althalus discovers Dweia in the form of a black cat and learns that she has chosen him to aid her in a war against Ghend and her evil brother, the destroyer god Daeva. Together Althalus and Dweia use the power of the Book and gather together a small team of questionable heroes who must battle Ghend's supernatural forces and armies. The thief Althalus can only hope his luck holds out for this one last task, since the very fate of humanity is at stake.