During a lull in the fighting, Galahad returns with the bad news that no one from Gwent is coming to reinforce them, except for perhaps a few volunteers. However, a handful of men from Kernow do come, led by Prince Tristan, who wishes to repay Arthur for fighting against Owain. As the fighting resumes, Derfel and his men are beaten further back. The battle stops once again as Cuneglas, Edling of Powys, offers them the chance to surrender; they refuse. Before the battle can recommence, Merlin arrives and commands both armies to cease hostilities because he needs all Britons to help him in his quest for the Cauldron of Clyddno Eiddyn, one of the lost Thirteen Treasures of Britain. Gorfyddyd is furious that Merlin has interrupted his chance of becoming High King, but Merlin is the most revered druid in all of Britain and therefore protected from harm. Gorfyddyd refuses Merlin's requests and readies his troops again for battle. Merlin, turning to Derfel, informs him that he has convinced Oengus Mac Airem's Blackshield Irishmen, previously allied to Gorfyddyd, to switch sides and give Arthur victory. Sure enough, as battle resumes, the Blackshields attack Gorfyddyd and surround his retreating shield-wall.