When a group of archaeology students from Oxford University set off to study an ancient stone circle, they have no idea they are about to be sucked into an age-old battle of good versus evil.

The Callanish Stone Circle has remained untouched for centuries, surrounded by the swirling mists of the Isle of Lewis. But while the ancient stones appear to be unchanged by the passing of time, somewhere a clock is ticking, getting ready to reveal the site's mystical secrets.

Forced to take shelter from a freak storm in a concealed labyrinth of tunnels below the stones, the students find themselves catapulted back in time, tasked with fulfilling the prophecy of legendary sorcerer Merlin. Will they be able to triumph over the forces of darkness or will this unfamiliar world of demons, magic and chivalry prove to be too great a challenge?

The Chosen Ones of Callanish is a fast-paced fantasy thriller in which two very different worlds collide. Will the modern-day protagonists manage to get to grips with the ancient virtues of honour, valour and chivalry before it is too late? And what price will they need to pay to survive?