Titus Cragg has been called to Moss Side Farm, near the town of Warrington in the south of the Duchy of Lancaster, where he finds the scene of a gruesome slaughter: a mother and her four children brutally murdered in their own home. Were they killed by the man who should have protected them: their husband and father? And what role is played by the peculiar religious cult the family belongs to? Perhaps the mute boy who is found still alive and living in the dog kennel knows the truth. The two vagabonds seen lately on the roads, but now missing, may also have information.
Meanwhile, Titus’s friend Dr Luke Fidelis is a guest of wealthy landowner, local magistrate and keen horticulturalist John Blackburne at nearby Orford Hall. While staying at the hall, Fidelis joins Cragg in looking into the farm killings, but he is distracted when a blackened but well-preserved body is dug up from the peaty ground beneath Blackburne’s hot-house, in which his gardener propagates many rare plants. A new investigation begins as Cragg and Fidelis examine the body, realising that it may have been in the ground for centuries. How then to make progress in uncovering the truth?
Gradually a complex tale is pieced together of secrets, scandals and thwarted passions – and a surprise connection is made between the body under the hothouse and the farmhouse massacre.