Hint 1
There is a coded message. What does it say? Who wrote it, and who left it in the sisters’ prayer area?

Hint 2
Look closely at how the letters are arranged. Do any positions in the alphabet come to mind?

Hint 3
What happens if the alphabet is reversed?

Hint 4
Try matching A with Z, B with Y, and so on

Hint 5
Use the Atbash cipher to decode the message. This may help explain both its author and how it was left behind.