Early 20th century France, you might want to keep your door shut and hang crosses all around your house… as supernatural phenomenons are increasing, you might find yourself in front of a ghost, an evil spirit, or worse! But fear not, Sister Clemence is on the case. After all, she is the church’s best and most trusted exorcist! However, upon investigating a strange case, her destiny changes forever when she meets M. Marcus who seems to suspiciously know a lot about supernaturals and demons.