The year is 1905 and Powerscourt is sent to Ireland to investigate a series of art thefts from stately houses. Motive troubles Powerscourt; were these robberies merely for gain? A number of Old Masters had been left untouched and the ones taken were all ancient family portraits of the aristocratic Protestant gentry. Are these thefts political?

Then, astonishingly, some of the portraits begin to return - but with altered faces; the aristocrats' being replaced by those from the estates and towns beyond the gates. Truly an elaborate joke, but then real people begin to disappear - and not long after the first body is found in the chapel at the top of Croagh Patrick, Ireland's Holy Mountain on the very day 10,000 people make the great pilgrimage to the summit.

More follow, and as Powerscourt makes his way towards the killer his own life comes under threat, while his patriotism, and his devotion to Ireland is called into question on his journey towards the truth.