Describe the incident with Mr. Barnett and Cassie?

If you are talking about their altercation at his store in Strawberry, the children go into Barnett's store so that TJ can purchase some items for his mother. When they're ready to order, Mr. Barnett leaves them standing while he waits on his white customers..... there's no line at the counter. After about an hour, Cassie speaks up, telling Barnett that he has forgotten them. Barnett responds with a number of racial slurs.

“Well, you just get your little black self back over there and wait some more,” he said in a low, tight voice.

“Whose little nigger is this!” bellowed Mr. Barnett. Everyone in the store turned and stared at me. “I ain’t nobody’s little nigger!” I screamed, angry and humiliated. “And you ought not be waiting on everybody ’fore you wait on us.”