S3, E12: In this first episode of a two-parter, Merlin and Arthur are sent on a dangerous mission to capture the Cup of Life, a powerful magical artifact that carries the gift of immortality. Before they can retrieve the Cup, they are captured by the unscrupulous slave trader, Jarl. Gwaine comes to the rescue and they escape, but with Jarl's help the cup falls into Morgause's hands. With an immortal army at their disposal, will Morgause and Morgana topple Uther once and for all?