In the summer of 1964, freedom workers come to a small Mississippi town to register blacks to vote. The quiet pace of the summer changes dramatically for Cooper and his friends Jubal, who is black, and Squirrel, who is Jewish. The only white member of Oak Grove Baptist Church, Cooper must decide how to react when his father makes him attend Ku Klux Klan meetings. His uncle Chicago helps guide him through the turbulent times.As the summer progresses, the pastor at the church learns of the Klan's plans in advance. He says the news comes from the Angel Gabriel. When Cooper discovers Gabriel's identity, he must decide what role he will play, and on which side.