S1, E5: Derfel feels uncomfortable about the attack on the mine – which Owain is keeping a secret. Nimue aborts her pregnancy, and then is discovered by Merlin who helps heal her. Tristan, prince of Kernow, arrives demanding retribution for the raid at the mine but Owain denies his guilt. Derfel reveals the truth and Arthur fights Owain on Tristan’s behalf – tragically killing his best friend.