Airs Sunday, September 25, at 6 p.m. The nation's high school graduation rate is at an all-time high, but high-poverty schools face a stubborn challenge. There is virtually no way to make a legal living these days without at least a high school diploma. Still, nearly 20 percent of students don’t finish. Why? This documentary explores what students and teachers are up against in some of the nation’s poorest high schools. We document the progress that has been made at one former “dropout factory” and ask what it would take to help more kids succeed. And we visit one school that literally chases students down to get them to class so they can graduate.