The Burning Altar — Sarah Rayne

Patrick Chance was a notorious Victorian rake whose memoirs of his travels through Tibet caused a sensation at the time. But, having retraced his ancestor's footsteps, Sir Lewis Chance is the only one who knows the truth. For he has also stumbled on the strange, secret tribe who guard the sinister Stone Tablets in remote Tibet. A group whose perverted beliefs, blood rituals and horrific customs have torturous, hellish consequences.