Frank Leone is a skilled mechanic and a model prisoner approaching the end of his sentence for a relatively minor crime. Grateful for the chance to finish his term in a low-security prison where he is able to go outside occasionally to see his girlfriend, Frank is unexpectedly transferred in the middle of the night to Gateway, a maximum-security facility run by Warden Drumgoole. Drumgoole bears a deep grudge against Frank for having previously embarrassed him and escaping from his previous institution, Treadmore, where Drumgoole was the warden. At Gateway, Frank is immediately thrust into a world designed by Drumgoole to break him before his impending release.

Amidst the brutal life of Gateway, Frank is subjected to constant harassment by the guards and targeted by violent inmates. Despite the adversities, he finds allies, including a wise old inmate named Eclipse who helps him navigate the prison’s dangers. As he tries to hold onto his sanity and principles, Frank is drawn into a series of confrontations orchestrated by Drumgoole, who is determined to provoke Frank into an act of aggression that will justify extending his incarceration. Frank must adapt to survive while holding to the hope of freedom, navigating through traps set by the vindictive warden whose sole aim is to ensure that Frank never sees the outside world again before completing his sentence.