This story starts one year after the end of the third book, in the early fourteenth century. The peaceful monastery of St Alcuin's is adjusting to its new abbot, who is taking the place of Father Peregrine, when an old enemy arrives seeking refuge. Reluctantly taking in Prior William, the upended community must address old fears and bitterness while warily seeking reconciliation. But can they really trust Prior William? In her fourth book in the series, Penelope Wilcock wrestles with the difficulties of forgiveness and the cautions of building trust. What is truly the hardest thing to do?