My least favourite of the series so far - I didn't like the ending and thought it was out of character for Cadfael to allow a murderer to escape.

With civil war disrupting the peace of Shropshire, new alliances are forming. The Sheriff, Gilbert Prestcote, is captured in a battle, and badly injured. Offered in exchange is a young Welshman who was left behind as drowned on a raid against a Shropshire convent. Elis is kin to a man close to powerful Welsh leader Owain Gwynedd, and Hugh Beringar, left in command in Shrewsbury, hopes the Welsh will agree to send Prestcote home. Brother Cadfael, himself a Welshman with kin in the border country, is sent as emissary to offer the trade.
Scarcely has Cadfael returned, and the injured Prestcote brought home by his Welsh captors, than all is upended. Someone, either in the Cloisters or among the Welsh delegation, smothers Prestcote as he lays sleeping in the abbey infirmary. Of the most likely suspects, Elis may be the most suspected, as a foreigner and with motive--he has fallen for Prestcote's daughter Melicent, and sought her father's approval. Did he in a fit of anger kill the man who stood between him and his passion? Or did the stableman Anion, with a grudge against Prestcote for executing his half-brother, take his chance to avenge an unjust death?
Meanwhile, the northern borders remain under threat, and Beringar and Gwynedd agree to share defense. But this draws men away from Shrewsbury, leaving the southern borders open to attack by another Welsh lord. Cadfael works to resolve the murder, even as he is drawn to help in the fighting. But can his efforts save the lives of two who are bound as brothers?
This is my first encounter with the fascinating Sister Magdalen, once the mistress of a wealthy baron, but now under the veil at Godrick's Ford, and rescuer of Elis the Welshman. I hope I can find more tales involving her, who seems a soulmate in spirit and wisdom to Brother Cadfael. I'll also be interested to see what befalls the Shropshire district as leaders change and alliances reshape the politics of a region destabilized by the imprisonment of King Stephen. Frankly, the history in this tale was more interesting than the murder.
Loving this series so far, as lately as I've come to it. I hope I can find more volumes as I am starting the last of three currently on my shelf.

I liked this one. The Welsh context was really interesting and the story rattled along. I didn't see the end coming either.

I just love the mystery and sense of things happening all at once to be sorted out later, but I do find the main girl to be a bit of a naïve and quite childish, apart from her the rest of the characters at rich and full of life especially the main ones throughout the series.