The Secret Mice is the title of a book by English author M. I. McAllister. The official synopsis is provided below:
The St. Michael's mice are no ordinary mice. When Rachel saves them from the church's mouse man, it just seems like a good deed. But it soon becomes clear that they are very special mice indeed. They can talk. And not only that, they have a very special task for Rachel to perform, one that will help her save her father's church. And they also have a mystery for her to solve which stretches back through generations, involving children who have lived in the vicarage. This work features good old-fashioned story-telling, with an interesting and sympathetic heroine, and a plot that draws together beautifully its various strands of history, magic, and mystery.