Death, the pious say, is the great mystery and Sister Frevisse finds it puzzling indeed. She has come to grieve for her uncle at Ewelme Manor, where his old friend Bishop Beaufort is also in attendance. Neither expected querulous Sir Clement Sharpe to stand at the funeral feast, dare God to strike him down and then actually collapse. With all the guests having supped on the same meat and wine without ill effect, was it indeed the Lord's hand that smote Sir Clement? The wily bishop suspects an unusual poison and orders Sister Frevisse to investigate. But the clever nun has her eyes open for something else; a killer with a venomous hatred...or a diabolical love.