Seemed to me there was an overarching back story but the few I watched seemed to be more about helping people out of trouble.
Yeah the beginning is just the premise of saving people and origins of the machine. Season three is when it started to develop deeper into AI vs AI, and bring new characters, who are smoking hot. Its The machine vs Samaritan, while also maintaining the original premise to some degree. The last 2 seasons are more indepth related to what Samaritan was actually capable of. I like Finch in the show, the creator of the machine and his ethical considerations for developing it like he did. I also like Reese because he's a phantom and I like that chit

lots of shootouts, critical thinking, clever cast and a storyline full of reasoning.
Its hard as hell for me to binge watch as well. Only recently have I been able to get into shows. I watched the first season of Westworld, which I really enjoyed. Been skeptical on the second by maybe I'll try it. There are so many, and being an hour long... you really have to make some tough decisions on which to actually watch
