Bath Abbey, 1199. The monks' peaceful existence is turned upside down when the Abbey's unpopular prior is found dead on Solsbury Hill. But when Sir Symon Cole and his wife, Gwenllian, arrive to investigate, they soon hear whisperings that the prior has met with divine punishment.

For it is said that on Solsbury Hill, only those who are pure in heart can survive a night when the moon is full.

Determined to get to the bottom of the suspicious circumstances surrounding the prior's death, Gwenllian launches a daring investigation that puts her in great danger and Sir Symon accepts a challenge to visit the hill at night.

Sacred treasures. Dangerous secrets. Plots against Church, Crown and Government. Solsbury Hill continues to be the scene of murder, theft and conspiracy throughout the ages. But what will today's archaeologists make of the mysteries uncovered on this haunted site?