The Winter King

High King Uther banishes his son, Arthur, who rescues a dying boy named Derfel; Arthur entrusts Derfel to Merlin and Nimue; Uther has a new heir, but Merlin receives a dark vision for the future.

An untimely death leads Merlin to locate Arthur and urge him to come back to Britain; chaos ensues when Gundleus assaults Avalon.

Arthur takes Gundleus prisoner, and Nimue begins to plan her revenge; Arthur learns that Gundleus' uncle Gorfydd is preparing for war.

Nimue returns to Avalon, where she is found by Merlin. Derfel and Owain travel to collect taxes from King Cadwys, but he convinces Owain to raid a nearby mine to settle the debt instead. The raid turns violent. Merlin discovers that Nimue is pregnant but refuses to help her perform an abortion – she runs away from Avalon. Finally, Gundleus returns with Gorfydd to Caer Cadarn.

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.

Arthur and the tribe kings enter peace talks. Arthur suggests that as a show of faith, he marry Gorfydd’s daughter, Ceinwyn. She is horrified by the news. Arthur and Derfel travel to Powys and rest for the night by a lake. Arthur meets Guinevere, Ceinwyn’s lady-in-waiting, but he doesn’t know who she is. They arrive in Caer Dolforwyn and Arthur and Ceinwyn are betrothed.