For many years, the people of Briton have enjoyed peace and prosperity under the reign of King Artor and the Union of Kings. Having spurned the despotism of his predecessor, Uther Pendragon, Arthur has ruled with a strong sense of duty, goodness and honour.

Artor is now weakening with age, however, and the seeds of discontent are being sown. Seeking to cleanse the land of Christian belief, dissenters need a symbol with which to legitimise their pagan claim and gather malcontents together into a cohesive weapon. These shadowy, subversive elements seize upon the ancient cup of Bishop Lucius of Glastonbury as a way of fragmenting Artor s hard-fought-for kingdom. But first, they must lay their hands on the relic and, in doing so, unleash a force for evil from which murder and violent mayhem ensue.

But it emerges that the ultimate threat to Artor s rule lies far closer to home; Artor is betrayed by kin. Celt will slay Celt and the river will run with blood.