What is the main conflict in Give a Boy a Gun by Todd Strasser?

Brendan Lawlor moves to Middletown from Springfield in the middle of his ninth grade year. While Brendan was a jock and popular in his previous school, his life changed when he came to a new town and a new school. Brendan becomes friends with Gary Searle, who is also an outcast at Middletown High School. Brendan finds himself struggling beside Gary with the other kids at school teasing them, making fun of them, and treating them as outcasts.