Years later, following the Grail Quest, Malory tells his readers that the pair started behaving carelessly in public, stating that "Launcelot began to resort unto the Queene Guinevere again and forget the promise and the perfection that he made in the Quest... and so they loved together more hotter than they did beforehand." They indulged in "privy draughts together" and behaved in such a way that "many in the court spoke of it." Guinevere is charged with adultery on three occasions, including once when she is also accused of sorcery. Their now not-so secret affair is finally exposed by Guinevere's sworn enemy and Arthur's half-sister, the enchantress Morgan le Fay who had schemed against her on various occasions (sometimes being foiled in that by Lancelot, who had also defended Guinevere on many other occasions and performed assorted feats in her honour), and proven by two of the late King Lot's sons, Agravain and Mordred. Revealed as a betrayer of his king and friend, Lancelot fights and escapes. Incited to defend honour, Arthur reluctantly sentences his wife to be burned at the stake. Knowing Lancelot and his family would try to stop the execution, the king sends many of his knights to defend the pyre, though Gawain refuses to participate. Lancelot arrives with his kinsmen and followers and rescues the queen. Gawain's brothers Gaheris and Gareth are killed in the battle (among others, including fellow Knights of the Round Aglovale, Segwarides and Tor, and originally also Gawain's third brother Agravain), sending Gawain into a rage so great that he pressures Arthur into a direct confrontation with Lancelot.