The film is set in a dystopian future where law and order are enforced by the Judges, who act as judge, jury, and executioner. The story follows Judge Dredd (played by Karl Urban), a no-nonsense law enforcer with a reputation for strict adherence to the law.

Dredd is tasked with evaluating a rookie Judge, Cassandra Anderson (played by Olivia Thirlby), who possesses psychic abilities. The two are sent to investigate a series of murders in a high-rise building known as Peach Trees, a massive and crime-ridden tower block controlled by a powerful drug lord named Ma-Ma (played by Lena Headey).

Upon their arrival, they discover that Ma-Ma’s criminal empire is based on a new and highly addictive drug called SLO-MO, which causes users to experience time at a slowed-down rate. Ma-Ma’s gang takes notice of Dredd and Anderson’s presence, leading to a deadly confrontation.