Apparently, after writing A Morbid Taste for Bones, Ellis Peters was not planning to use her detective, Brother Cadfael, again. However, having devised the plot for One Corpse Too Many, she realised how useful he could be and thus the 21 volume series was born.
In this book civil war is raging with Stephen and Maud battling for the crown. Stephen is besieging Shrewsbury Castle and, incensed by their defiance, once he has broken in he has all the garrison hanged from the ramparts. Brother Cadfael is sent by the Abbot to arrange a seemly burial for the executed rebels. On counting the corpses, he finds there is one too many and that one has been garrotted, not hanged.
As the new helper in his herbarium is the disguised daughter of one of Maud's most powerful supporters and her father escaped from the besieged castle, Cadfael is drawn into the murder mystery and the reader experiences a version of mediaeval life which is alluring if not perhaps totally realistic. Here noble men are incorruptible, justice is always done and even the beggars and lepers seem sanitised.
But nobody who has wandered into Cadfael's herbarium or smelt the crushed herbs on a warm summer afternoon in his garden will be over-critical of Ellis Peter's version of twelfth century England/Wales. It is an irresistible journey into the past.