‘Reacher’ is based on the book series of the same name by Lee Child, with each season adapting a different book. The fourth season is set to focus on ‘Gone Tomorrow,’ the thirteenth book in the series, which takes Reacher to New York. Since the filming is taking place in Philadelphia, it remains to be seen whether the show will change the location or if it’s simply using The Quaker City to sit in for the Big Apple. In any case, the creators of the show have promised that the season is even more high-octane than the previous ones, and according to lead actor Alan Ritchson, it features the best fight scene in the show so far. Considering the places that Reacher goes in the story, he has a lot of fights in his future., Based on the Jack Reacher book series by Lee Child, it stars Alan Ritchson as the title character, a self-proclaimed hobo and former U.S. Army military police officer with formidable strength, intellect, and abilities., The fact, however, remains that this case will take Reacher down a very dark path. Reacher Season 4 Has an Entirely New Cast Because Jack Reacher moves around so much and the stories are so starkly different from each other, there is rarely a situation where a character repeats in the show..