The Shortest Day

From the publisher: "In Ireland, a man of reason is drawn to a true mystery older than the Pyramids and Stonehenge in this enthralling story about ethereal secrets. During the winter solstice, on the shortest day and longest night of the year, the ancient burial chamber at Newgrange is empowered. Its mystifying source is a haunting tale told by locals. Professor O’Kelly believes an archaeologist’s job is to make known only what can be proved. He is undeterred by ghost stories, idle speculation, and caution. Much to the chagrin of the living souls in County Meath. As well as those entombed in the sacred darkness of Newgrange itself. They’re determined to protect the secret of the light, guarded for more than five thousand years. And they know O’Kelly is coming for it."