Merlin Season 2 Episode 11

Mordred brings a warlock, Alvarr, to see Morgana and they persuade her to steal a crystal with magical properties from the vaults of Camelot. Alvarr tells her it can be used to help people like themselves with special powers though he really intends to destroy Camelot. Merlin and Arthur pursue him, returning him and the crystal to court, though Mordred escapes and Morgana, having disowned Pendragon, springs Alvarr from prison by drugging the guards. Merlin,having looked into the crystal, is alarmed by a vision of chaos but Gaius assures him that it is far into the future.