When Merlin discovers the beautiful druid girl Freya trapped in a bounty hunter's cage, he knows he must help her escape. Gaius warns against getting involved, but Merlin refuses to listen, harbouring Freya in the tunnels beneath Camelot. But with the bounty hunter searching for his missing prize and a ferocious magical beast on the loose, Freya cannot stay hidden for long.

Merlin's intense new friendship is tested to the limit, and he is forced to make some heartbreaking decisions as he battles to keep Freya safe.

Uther has a precious magical relic of the Old Religion locked up tight in the Camelot vaults. Many have lost their lives trying to reclaim the Crystal of Neahtid, but the ruthless warlock Alvarr could succeed where they failed. For Alvarr has a secret weapon - Mordred.

Morgana has always shared a powerful bond with the druid boy, but will she go as far as turning thief and traitor for him? Merlin is shocked by her choice, and by the true purpose of the mysterious crystal.