Rhys, a common Briton bard who suffers from bad lungs, and nary a hero nor skilled fighter among noblemen and powerful clerics, is tasked to investigate the disastrous fall of the fortress Castrum Tenebrarum, besieged by Saxon hordes. In the abandoned ruins, he uncovers a hidden tangle of enmities, a beautiful woman imprisoned in the buried vaults, and a bloodletting ritual described in bardic tales from King Arthur's court three generations earlier, when valiant Knights of the Round Table stemmed the tide of an invasion by bloodthirsty monsters. Smitten by the woman, Rhys learns of the Black Knight's hold on her and sets out to destroy him in hopes of freeing her from a terrible curse. The journey tests his mettle, hones his swordsmanship and wits against deadly revenants, and forces him to choose between the love of this woman and duty to his beleaguered country.