The murder is reported to Shrewsbury Castle. Its active ingredient is monkshood (Wolfsbane), deadly if ingested. He realises that the sauce in which the partridge was served was poisoned by a liniment he made. Cadfael recognises Bonel's widow as Richildis Vaughan, to whom he was informally betrothed over 40 years earlier. Brother Cadfael the herbalist and Brother Edmund the infirmarer run to his aid but cannot save him. Bonel is taken ill immediately after eating it. He receives gifts meant for the Abbot, including a fat partridge which he shares with Bonel, having his cook send a portion with dinner. Prior Robert is left in charge of the Abbey.

All expect that Heribert or his successor will complete the agreement after the council. The Abbey's business is also postponed, with one exception: Gervase Bonel, who has ceded his manorial estate at Mallilie to the Abbey in return for a small house where his needs in retirement will be provided, is allowed to move his household before the charter is signed. In early December 1138, Abbot Heribert of Shrewsbury Abbey is summoned to a Legatine council in London and his authority is suspended. Another reviewer missed the lively character of the second novel, Hugh Beringar, wishing him to be more involved in this plot, yet saying 'Peters does wonders with the medieval scene and with complex character relationships.' Plot summary

The author was commended by one reviewer for her ability to draw characters who are distinctly medieval, 'not modern men and women masquerading in medieval garb,' while dealing with fine points of medieval Welsh law. This novel received the Silver Dagger Award in 1980 from the UK's Crime Writers Association. The sergeant views the case differently from Cadfael. Who used it as poison? Cadfael assesses the motives of Bonel's family and household staff, including his Welsh natural son and his stepson, and deals with Bonel's widow who was once Cadfael's sweetheart long ago. Gervase Bonel dies from monkshood oil put in his food.

It was adapted for television in 1994 by Central for ITV. It was first published in 1980 ( 1980 in literature). It is the third novel in The Cadfael Chronicles. Monk's-Hood is a medieval mystery novel by Ellis Peters, set in December 1138.

Monk's Hood by Ellis Peters