Behind the Wax Seal is a novelette about a 16-year-old girl named Sarah. Set in the present day, Sarah finds a letter with a 1942 postmark. On reading it, she finds it was written to her recently deceased grandmother by a friend named Mary. Intrigued by the ink color and wax seal, Sarah embarks on a quest to find out more about Mary, who she was, and how her friendship figured into her grandmother's life. Sarah then learns about Mary, her challenges and illness, and how her faith in God and Scripture not only sustained her but also touched and changed Sarah's life seven decades later.