It's Christmas Eve, and under the floorboards of G. K. Chesterton's home, curious clues lie hidden... Sister Seraphina and the other Sisters of Our Lady Star of the Sea are busy with preparations for the Christmas play and long-awaited feast. That's enough to be getting on with! But where is Sister Dymphna? The elderly nun is nowhere to be found in Saint Wulfhilda's Abbey. Outside it's growing dark, and the snow is falling. The brave search party will need all their wits to avoid danger and follow the trail--wherever it leads!