The Key of Bones is the fourth story of the third series.
Part 1 Edit
As more tears appear in the Line of Twilight, Tom's grandfather proposes a quest for a lost artefact with the power to heal it, which Lady Lyzera is also determined to find.
Part 2 Edit
Negotiating perilous puzzles in an ancient castle, who will prove worthy enough to possess the one artefact that can save the world – or destroy it?