A church mouse is no ordinary mouse, and Hildegarde - the Mouse Mistress of Saint Bartholemew's - is no ordinary mouse leader. It falls to her to keep all the church mice safe and out of sight.

But when a few parishioners report mouse sightings, Hildegarde and the rest of the church mice must face a most dreadful consequence: the Great X. To complicate things, a ceremony called the Blessing of the Animals is fast approaching. Saint Bartholemew's will soon be filled with pets . . . including cats!

Oh, dear. Within the stately stone walls of the church, life is not as serene or safe as one might think. It will take the courage and patience of a - well, of a saint - to keep this scampering, squeaking tribe of Hildegarde's intact.