housing unit known as the shu, a prison within a prison. shu inmates spend about 22 hours of every day in solitary confinement locked up in an 8 x 10 windowless cement cell with little human contact. inside the shu are about 1,000 level four prisoners, what boyle calls the worst of the worst. inmates that other wardens don t want or can t handle. dangerous gangs founded within the penal community. because of their gang leadership, they have the authority to authorize other people in the community or the prison to commit these types of crimes. and on that day, two alleged gangs go to war. it s sunday, and it s raining. 200 shu prisoners are released into b yard for exercise. boyle says that the entire prison is on edge dating back to a smaller racially charged riot six months earlier between two gangs, the southern hispanics and the black guerilla family.