Animal Factory (movie, 2000)

Suburbanite Ron is spoiled, young and not overly worried about the marijuana charges leveled against him. But, after being made out to be a drug dealer, he faces a five-year jail sentence in San Quentin State Prison. Physically frail and unaccustomed to his rough surroundings, Ron is primed to fall victim to sexual predators and bullying guards – that is, until he's befriended by Earl, a veteran inmate who finds meaning in protecting the vulnerable new kid.