This British author has before applied her storytelling agility and haphazard scholarship to ancient British period mores and speech (The Gods Are Not Mocked, 1968); here she roughs up the Tristan and Isolde tale (in her version ""Drustan and Essylt"") with remnants from Malory, Belloc, ""early legends"" (unspecified), and lore concerning a fading Druidic tradition and raw Christianity. But she comes up with a fine noisy tale. It was Drustan's stepmother, Queen to King Cynmor, who, after attempting to poison him, warns Drustan he will become a wanderer. Wander he does -- to his uncle King Mark's court; to the end of Arthur's kingdom where he places Arthur's body on a boat with the Hooded Three; to the semi-priestess Deirdre, mother of Essylt; to the ""school of the Druids""; and finally the fatal voyage to bring Essylt to the bridegroom Mark. Once the love potion is shared, Essylt and Mark are whirled together and apart again and again in love's madness until the final liebestod. There are so many escapes, omens, sword swipes, and ecstasies that the reader may just forget such sallies as: ""Don't quote my words back to me. . . I'm not one to be kept in a cage of relationships."" Along with the gaffes -- an entertaining picaresque.