In this chapter, Joseph sets up a prank of Biblical proportions to play upon his ten brothers. He pretends to be an Egyptian native (not hard to pull off as steward to the king) by speaking to them through an interpreter, accuses them of being Canaanite spies come to discover the strategic weaknesses of Egypt, and slams them all in jail for a few days. He also does a little spying of his own, listening in on his brothers as they speak Hebrew to one another on the reasonable assumption that Joseph (who goes by the Egyptian name of Zaphnathpaaneah) cannot understand what they are saying.
Joseph then has his brother Simeon bound and sends the other brothers on their way back to Canaan and their father, complete with stores of food and with a surprising refund of the money which was intended to pay for the food. But this prank is just getting started.