Sister Austere.

At the convent, nobody has ever seen Sister Esther smile, which explains the nickname she received! But Sister Austere is also known for her steadiness, and it is her who is chosen one day to go out and look for the young novice Mathilde, who just escaped from the convent. However, this little trip will turn out to be far from trivial for Esther, whose big secret will eventually be revealed.