Noah comes to Fagin's the next morning for breakfast. Fagin congratulates Noah on the trinkets he stole from children the previous day, after checking on the Dodger at the court. Fagin says he has a new proposition for Noah: that he act as a spy on a "young woman." Noah readily agrees to this. Fagin himself spies on Nancy for six days, and realizes that, on Sunday, she intends again to go out to see her "lover."
Noah is happy to perform any task that does not seem to offer him the possibility of physical harm. Spying, then, is a perfect activity for Noah—one that allows him to be of use for Fagin, and which keeps him, or so he thinks, significantly out of harm's way.
Fagin takes Noah to the Cripples pub that Sunday evening, and, through the trick pane of glass in the secret room (from which Fagin once observed Noah), Noah observes Nancy. He says he would recognize her anywhere, and will follow her the whole night. Fagin wishes him good speed, and after Nancy has left the Cripples for her meeting, Noah heads out after her, directed initially by Barney (holding open the tavern door), and into the night.
A motif is then developed in the novel: of conversations being overheard, or partially overheard, by other characters. Noah is spied on by Fagin, earlier, and Fagin blackmails Noah with that information; then Noah is tasked with doing the same thing to Nancy.