The Grail Delusion

It is 20 years since the Hengest and his followers were driven out of Britannia by Aurelius Ambrosius and Childric, his kinsman, wants revenge and the reconquest of what he calls "Angleland", but he realises that it will be impossible while Merlin lives, so he asks Angle wise woman, Morwei, to create an illusion of the Holy Grail to bring about the death of Merlin and lure Arthur's marchogion to their destruction - but will it fool the sagacious wizard?