The basic premise of the play is that there is a man named Demos (Greek for "The people") who is not very bright. His slaves, Nicias and Demosthenes (Aristophanes did not change the names of whom these characters portray.), are displeased with the way Demos' steward, the Paphlogonian (aka Cleon) has been treating both Demos and the other slaves. They discover that the way to remove the Paphlogonian from power is for him to be replaced by a Sausage-Seller.
The two slaves find the Sausage-Seller, and explain their predicament to him. He is more than willing to help.
The play then degrades into the Sausage-Seller claiming he will do all the terrible things that the Paphlogonian did for Demos, and more! The two trade insults, and try to out-do one another in their absurdity and crudeness. In the end, Demos decides that he will take the Sausage-Seller as his new steward, and we discover that the Sausage-Seller really was a good guy all along and only said the things he said to get the job.
This play is also notable for its unflattering view of the people as dumb, easily fooled, and fickle.