At St. Louis County Jail, some of the inmates are on edge, and only one thing's for sure: Somebody's going to cross the line. Here, small-time offenders sleep next to career felons and collide with each other in open areas during the day. Tensions could erupt at any moment, but for each unit of 67 inmates, there's just one corrections officer - armed with nothing but a panic button and pepper spray - to keep all hell from breaking loose.