Ave and her best friend Katie lived for many years as nuns in a convent in Nimbschen. But one day the two women and several other nuns decided they must flee the convent for the city of Wittenberg so that they could worship the Lord in a way pleasing to him. Ave and Katie both eventually married. Ave moved away from Wittenberg, while Katie remained in the city with her new husband, Dr. Martin Luther. Over the years the women wrote each other many letters and remained close friends, "sisters in the Lord." Now almost three decades later, Ave has received a letter that Katie has died. Determined to share her friend's faith, Ave begins to relay her memories of Katie and share the letters she has kept for all these years. Ave desires that we learn what her friend Katie came to learn over fifty-three years on this earth: trust in the Lord. He strengthens the hearts of all who hope in him (Psalm 31:24).