As nuns go missing in a late 17th century Benedictine convent, Abbess Agatha must root out the evil lurking in her priory. With one particular sister's behaviour becoming terribly erratic, she suspects the Devil himself is at work. The aftermath will leave a cypher so inhumanly complex—it wouldn't be deciphered for nearly four centuries.
In Italy, that letter is still safeguarded today.
S3•E1 Letter from the Devil, 1676
