The pastorelas usually lasted as many hours as it had devils. Most pastorelas had three devils (as this one being discussed) therefore, lasting three hours. In Act I, the shepherds after being told by the angel, are on the way to Bethlehem to adore the baby Jesus. Their journey is interrupted by a (veiled masked) person. The shepherd's don't show concern since most wealthy people wore masks at the time. Bartolo, on of the youngest shepherds, cautions the others because this stranger leaves a lingering smell of sulfur.

As their journey continues, seven strangers appear and try to keep the shepherd from going any further. A physical fight erupts between them, encouraging the shepherds to complete their journey. The Angel reappears and verifies their suspicion that the seven strangers were devils, so he gently guides them along.