Due to the large-scale radiation and pollution caused by nuclear war, the future United States has become a devastated wasteland. On the east coast, between Boston and Washington, D.C., there is a metropolis called "Megacity One", and more than 4 million people live in perpetual fear. It covers not only a vast area, but also crime and violence, as well as people who manage and control these chaotic blocks. They are all overbearing criminals ... and the burden of maintaining order in this city falls on a group of policemen called "special police judges". In view of the particularity of the times, they have the supreme power of trial, ruling and immediate execution of death penalty, which is the highest embodiment and symbol of the law and also the fight against violence with violence.

The well-known and revered Dred (downtown Karl) is the final judge. Now he is trying to get rid of the recent threats and disasters in this city. A very dangerous slow drug suddenly became popular, and his task was to trace its source.

One day, Dred fulfilled his responsibilities and obligations as a judge as usual, and at the same time accepted the assignment from the top to train and evaluate whether the trainee judge Cassandra Anderson (olivia thirlby) is qualified to enforce the law independently. Thanks to the gene mutation caused by radiation, Cassandra has a strong spiritual power. A heinous crime led Dred and Cassandra to neighboring areas, and even brave judges dared not take risks casually. This is a 200-story building, and now it has become a slum, manipulated and controlled by Madeleine (lena headey) and her minions. As a disgraced former prostitute, she has deep resentment and hatred for this society. With the combination of temporary partners' judges catching a core figure of this criminal organization, Madeleine's raging anger was finally ignited, and then a dirty and vicious war was launched against all judges. She wants to prove to everyone that she can protect her kingdom at all costs ... When the bodies are piling up, Dred and Cassandra realize that they have no choice but to face almost zero odds and try to find a way out in this battle.