Late December, 1389. Ordered to undertake a gruelling three-day journey to bleak Whitby Abbey in the far north of England in a bid to purchase the Abbey's priceless Holy Relic - a lock of St Hild's hair, said to be 700 years old - Hildegard of Meaux and her three companion monks arrive to find the Abbey a decidedly unwelcoming place, a place of strange customs and practices very different to their modest lifestyle at Meaux. Nor, as Hildegard discovers, is she the only visitor intent on acquiring the Relic.

Before the bidding war can begin, a body is discovered in the monastery's apple store shed, and once again Hildegard is plunged into a baffling murder investigation where nothing is as it first appears. Something is rotten in the heart of Whitby Abbey - and it's up to Hildegard to discover the truth.