12 Monkeys Season 4 Recap & Ending Explained

Here’s a breakdown of what happened in 12 Monkeys season 4 and its finale. Loosely adapted from the 1995 Terry Gilliam movie of the same name, 12 Monkeys premiered on Syfy in 2015. The series focuses on James Cole (Nikita’s Aaron Stanford) who is recruited by a team of scientists calling themselves Project Splinter in the year 2043 to travel back in time to 2015. His mission is to prevent a mysterious organization named the Army of the 12 Monkeys from releasing a deadly virus that will decimate most of the human population.

Throughout the first three seasons of 12 Monkeys, Cole – with the help of virologist Dr. Cassie Railly (Suits’ Amanda Schull) – traveled back and forth in time trying to discover the identity of the Army of the 12 Monkeys’ leader, an enigmatic individual known as The Witness. Unfortunately for its fans, 12 Monkeys’ fourth season was it’s last but it was certainly an eventful one.

As should be expected of a time-traveling drama, 12 Monkeys season 4 was full of twists and turns. With the knowledge that Olivia is the Witness, Cassie is sent back in time to 1971 to kill a teenage Olivia before she can wreak havoc. Just as she’s about to shoot Olivia, her mother Mantis takes the bullet for her. Meanwhile, Jennifer (Emily Hampshire) has stolen an ouroboros artifact which leads them to Montana in 1852. There, Team Splinter finds Jones’ (Barbara Sukowa) husband Elliot (Peter Outerbridge) who is building Titan for the Army of the 12 Monkeys. He’s sent back to Jones in 2046 where they realize Olivia doesn’t just want to travel through time but punch a hole right through it, thus creating the Red Forest.

Luckily, the Primaries have been assembling a weapon capable of destroying Titan that involves a cryptic message; ‘Climb the stairs. Ring the bell’. This takes Team Splinter first to Nazi Germany and then to the Middle Ages but Olivia and the Army of the 12 Monkeys stop them from activating the weapon. Soon, Team Splinter realizes the Primaries’ intention wasn’t for them to prevent the virus being released but to erase Cole from all timelines and restore proper causality. It’s also revealed Jones’ daughter Hannah (Brooke Williams) is Cole’s mother just before she takes a bullet for him.

In the two-part 12 Monkeys series finale, Team Splinter realizes their computers aren’t capable of calculating the code needed to erase Cole from time. Titan’s computers are, however, so they launch an attack on Titan and a massive battle ensues. Cassie defeats Olivia but has last-minute misgivings about loading the code as it means losing Cole but just as time is about to collapse Cole convinces her. They share one last kiss before everybody heads home to their respective timelines, ending the plague and saving time. There’s a twist at the end of 12 Monkeys season 4, however. It turns out Jones found a way to save Cole by inserting him into the new timeline where he happily reunites with Cassie.