In the apocalypse of 2163, a desperate Cole searches for Titan. Meanwhile, a captive Railly is faced with an impossible choice as the 12 Monkeys await the arrival of The Witness.

Travelers come face to face with ghosts from their past when they find themselves maneuvering around their own timelines.

The final battle against the Witness as the fate of time and mankind hangs in the balance. All the pieces finally come together to mark the end of the beginning.

When all hope is lost, Cole must complete his cycle so that his younger self will one day arrive at the end with the answer.