It is the last day of Dill's stay in Maycomb for the summer, and he and Jem plan one more attempt at getting a peek at Boo Radley. The children's innocent raid on the Radley's back porch turns dangerous, however, when first a shadow appears above Jem. Jem covers his head and "went rigid," expecting the worse, but the shadow--almost certainly that of Boo--passes by and the children run for their lives. A shotgun blast signals that the children have been discovered, and when Jem becomes trapped on the Radley fence, he is forced to remove his pants. The children are forced to lie to Atticus about why Jem is wandering the neighborhood in his underwear--Dill quickly comes up with the idea of strip poker--and they go to bed safely assuming that Atticus does not know the true story. But Jem's conscience is bothering him, and he decides to return for the lost pants. He does not want to risk being punished by his father--
"Atticus ain't ever whipped me since I can remember. I wanta keep it that way." (Chapter 6)
but he is more ashamed at having deceived Atticus and possibly losing his trust. Jem returns safely with the pants, and it will be his last foray onto the Radley property in search of Boo. But there is a secret that he withholds from Scout, waiting a week before telling her: His pants were waiting for him, folded and mended, on the Radley fence. Jem does not say it out loud, but he knows that it is Boo who left them that way--a friendly gesture from the man who has been leaving them the gifts in the tree.