In chapter 18 who does Tom find in his lodging in St Louis? What is wanted of him?

Roxy escapes from her Arkansas plantation and returns to St. Louis. Roxy is angry that she has been betrayed by her own son. She orders Tom to go to his uncle, confess what he has done, and get the money to buy back her freedom. Roxy threatens to go to the judge and tell him everything if Tom does not do this.