We couldn't find a cover image for this book but we did find it listed on Amazon
When a young nun, Joanna Calverley, dies of fever in the town of Beverley, they waste no time in burying her, fearing the plague. But nine months later a woman turns up claiming to be Joanna, saying she faked her own death. When murder follows close on her heels, John Thoresby, Archbishop of York, knows he must enlist the help of his favourite detective, Owen Archer. While Owen sets off for Leeds and Scarborough to speak with the Percy family and Geoffrey Chaucer, who is spying for the King, his wife Lucie tries to discover from Joanna the events of her missing year. Soldiers fleeing to France, relic-trading and incest are just a few of the secrets which emerge.