12 Monkeys was a Syfy network series, loosely based on the 1995 Terry Gilliam film of the same name, which ran for 4 seasons/47 episodes, from 2015-2018. It focused on a near future post-plague world and the survivor, James Cole (Aaron Stanford), who is sent back in time from 2043 to the decades before the plague in order to stop the deaths of 7 billion people.
Though the series uses concepts and characters from the film, it’s largely left the plot of the film behind by the end of the pilot. In the original 12 Monkeys film, the Army of the 12 Monkeys is a red herring. In the series, it’s a vast, secret organization which is responsible for the plague. Cole and Katarina Jones (Barbara Sukowa), the scientist who sends him back in time, assemble a time traveling team who oppose the Army of the Twelve Monkeys and their mysterious leader, the Witness, in a war to control the fate of the timeline.
In the future, post-plague world, Katarina Jones and her people find a damaged recording made in 2017, at the height of the pandemic, by Dr Cassandra Railly (Amanda Schull), a CDC virologist who specializes in epidemics. The recording asks “Cole” to hurry and names “Leland Frost” as the originator of the plague. With this starting point and a time machine that barely works, Dr Jones sends James Cole, a barely civilized scavenger, back in time to interview Dr Railly in order to learn further details about the start of the pandemic. His mission is to use the knowledge he gains from Dr Railly to stop the plague virus from being released.