As the story opens, an unnamed narrator reads in a newspaper about the arrest of his brother Sonny for using and selling heroin. This unnerving revelation causes him to think back to their childhood, when Sonny was "wild, but he wasn't crazy" (4).
The narrator is sort of shell-shocked the whole day as he tries to teach his classes. (He's a high school math teacher and he can't help but compare Sonny to the guys in his class.) He somehow makes it through the day and as he's getting ready to leave he runs into one of Sonny's old friends, who seems like he wants to get something off his chest. It turns out that he feels a little responsible for what's happened to Sonny, since he is a heroin user himself. He was honest about how good it feels to get high when Sonny asked him about it. He also tries to explain to the narrator what it's like to be on drugs and why Sonny may have gotten hooked, but the narrator just ends up more frustrated and angry.