The play begins with a strange scene-a large net has been spread over a house, the entry is barricaded and two slaves are sleeping in the street outside. A third man is positioned at the top of an exterior wall with a view into the inner courtyard but he too is asleep. The two slaves wake and we learn from their banter that they are keeping guard over a 'monster'. The man asleep above them is their master and the monster is his father-he has an unusual disease.