It is the year 2035. In 1996 an unknown and lethal virus wiped out five billion people and only one percent of the population has now survived the decimating plague. In a grave new world in which the planet's surface has become uninhabitable, the few remaining humans must live underground and rely on time travel to try to preserve their fate. A convict reluctantly volunteers to be sent back in time to 1996 to gather information about the origin of the epidemy which, he's told, was spread by a mysterious "Army of the Twelve Monkeys". He must locate the virus before it mutates so that scientists can determine whether the cataclysm can be stopped before it is started. Unfortunately Cole is mistakenly sent to 1990, six years earlier than expected, is arrested, and locked up in a mental institution where he meets Dr. Kathryn Railly, a psychiatrist, and Jeffrey Goines, the insane son of a famous scientist...