In chapter 4, Scout unknowingly upsets Jem, who gets his revenge by rolling her in a tire directly into the Radley yard. Scout ends up crashing into the Radleys' front steps and sprints out of the yard once she regains her balance. Scout accidentally leaves the tire behind, and Jem is forced to retrieve it. When Jem criticizes Scout for acting like a girl, she narrates, "there was more to it than he knew, but I decided not to tell him." Shortly after the incident, Jem comes up with the Radley game, where they reenact rumors and legends surrounding Boo Radley in their front yard. Scout is reluctant to play the game for two reasons.
At the end of the chapter, she explains that the first reason she didn't want to participate in the game concerned Atticus finding out. Scout recognizes that Atticus would not approve of the Radley game and does not want to get in trouble. The second reason concerns the possibility of Boo Radley watching them play the game and seeking revenge. Scout describes what she heard on the day of her accident by saying,
Through all the head-shaking, quelling of nausea and Jem-yelling, I had heard another sound, so low I could not have heard it from the sidewalk. Someone inside the house was laughing."
Scout suspects that Boo was the person laughing inside his home, which confirms that he is alive. At this point in the story, Scout still fears her reclusive neighbor and believes Boo Radley is capable of attacking them if he discovers their game. Despite her fears, Scout relents and participates in the game.