In 2035, humans were attacked by a virus developed by 12 monkey armies. Most humans died in this virus disaster, and only a few survived, but only survived in the dark underground. The scientists decided to send someone back in time to trace the history of 12 monkey armies in 1996. Prisoner James Cole (Bruce Willis Bruce Willis) is selected as a volunteer. Mistakenly, Cole goes back to 1990, and when he describes the future catastrophe to people at the time, he is caught as mentally ill and diagnosed with schizophrenia by doctor Catherine Shirley (Madeleine Stone Madeleine Stowe). Cole escaped with the help of patient Jeffrey Goynes and returned to the future. After failing to find out the origin of the 12 Monkey Army, Cole was sent back to 1996. Cole found the birthplace of the 12 Monkey Army in Philadelphia, he found the doctor Catherine, the two embarked on an adventure to track down the 12 Monkey Army!