As he walks home from the fire station, Montag meets a girl named Clarisse McClellan.
Clarisse is a pedestrian in a world where people do not take walks. In a sense she is the voice of the author, Ray Bradbury, who was concerned that technology would desensitize people and they would no longer think for themselves if they did not read or truly communicate with others.
After she asks, "Do you mind if I walk back with you?" Clarisse and Montag walk together on the "silvered pavement" that seems to give off the scent of apricots and strawberries, but Montag knows that it is too late in the season for such fruit. Yet Clarisse comments that she likes to smell things and sometimes stay up all night to watch the sun rise. Montag is somehow moved by this girl in whose eyes he sees himself reflected, for he feels strangely comfortable with her.
As she talks with Montag, Clarisse asks him why he laughs when she has not said anything that is humorous; further, she remarks that he does not ponder anything that she asks, but "answers right off," instead. These observations of Montag indicate that he has been desensitized by his world. After being with Clarisse whose last words to him are "Are you happy?" Montag begins to ponder whether he is, indeed, happy. As he walks in the darkness, Montag realizes, "He was not happy. He said the words to himself."
He wore his happiness like a mask and the girl had run off across the lawn with the mask and there was no way of going to knock on her door and ask for it back.
Clarisse McClellan has become the agent of change in Montag.