David Nelson, a soft-spoken but principled maths teacher from an obscure boarding school in the north-west of England, finds an intriguing and ancient artefact while in Paris.

Follow David on a perilous international quest as his research transforms legend into history, uncovering the far-reaching plot of a small group of zealots hell-bent on revenge.

Will he be able to solve the centuries-old arcanum of the Doomsday Calendar and prevent a disaster of Biblical proportions?