A small-town English teacher, Jake Epping, learns from a friend that there is a portal that leads from the present back to 1960. Jake's friend asks him to help him stop John F. Kennedy's assassination by going back in time and finding out who really killed Kennedy... and killing them.

It's October 1962, and the gathering storm of threats in Dallas continues to build. Jake must take drastic action to establish the full dimensions of the threat to Kennedy. And amidst it all, he's hit with an unexpected death and a bitter betrayal from one of those closest to him.

The end is near, and Jake is not up to the task. Sadie scrambles to pick up the pieces, but no one knows the mission as well as Jake. Kennedy and the assassin are on a collision path - but has Jake changed things enough in the past to alter the course of events? The days are counting down as 11.22.63 draws near.