What is the first of Modou's secrets that is revealed?

Modou had serious financial problems. Because of this, he had accepted a promotion in exchange for which he would tame the trade union struggle. In spite of this, he dies penniless and leaves behind many debts. Modou had abandoned his first wife (the narrator) and her children to live with Binetou. He had spent and borrowed large amounts of money to make his new wife and mother-in-law happy. One of the purchases he made was a nice villa for which he had planned to make payments for ten years.