Warning: Wikipedia contains spoilers
Twelve Monkeys is a Science fiction conspiracy-theory movie directed by former Python, Terry Gilliam, and inspired by the short film La Jetee. It deals with problems of time and memory, and features a memorable performance by Brad Pitt as a seriously deranged animal liberationist.
Bruce Willis stars as James Cole, who has been (ostensibly) dispatched back in time from a future world in which mankind lives underground in the wake of an apocalypse to learn from the events which led to the apocalypse; alternatively he could be just plain insane. On his arrival back in 1996, Cole is arrested and institutionalised whereupon he encounters Jeffrey Goines (played by Brad Pitt) and also meets Dr Kathryn Railly (Madeline Stowe), an expert in insanity related to prophecy. Initially Railly has Cole down as delusional, but as events unfold she begins to take him seriously.
Struggling with his own sanity, Cole, assisted by Railly, strives to unravel the mystery of the Army of the Twelve Monkeys. In the end it transpires that Goines and the Twelve Monkeys were not responsible for the spread of the disease which afflicted mankind but another person altogether...