Merlin (2008)

S01E12 To Kill the King

Gwen's father, Tom, assists a sorcerer named Tauren in using a magical stone to transform lead into gold. However, as Tauren makes his getaway, Tom is apprehended and faces trial. In her search for Gwen, Morgana stumbles upon the enchanted stone, which Merlin detects. When Uther kills Tom, Morgana vows to take revenge on Uther for his actions.